+2 - physics em vvi 1mark qb by raja sheker.pdf

8/18/2019 +2 - physics EM vvi 1mark qb by Raja Sheker.pdf

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1 V.P.Rajasheker M.Sc.,B.Ed., M.Phil., Mob : 9994472749

C o m p l e t e q u e s t I o n b a n k

repared by

v. p . r a j a s h e k e r

M.Sc., b.ed., M.Phil., p.g. teacher in physics

achariya siksha mandir

villianur puducherry 10

mobile : 9994472749

STD : 12 SUBJECT : PHYSICS

1. ELECTROSTATICS

ONE MARKS – BOOK BACK(V V I)

1.1 A glass rod rubbed with silk acquires a charge of +8 × 10−12C. The number of electrons it has gained or lost(a) 5 × 10−7 (gained) (b) 5 × 107 (lost) (c) 2 × 10−8 (lost) (d) –8 × 10−12 (lost)

1.2 The electrostatic force between two point charges kept at a distanced apart, in a medium εr = 6, is 0.3 N.The force between them at the same separation in vacuum is(a) 20 N (b) 0.5 N (c) 1.8 N (d) 2 N

1.3 Electric field intensity is 400 V m−1 at a distance of 2 m from a point charge. It will be 100 V m−1 at a distance?

(a) 50 cm (b) 4 cm (c) 4 m (d) 1.5 m1.4 Two point charges +4q and +q are placed 30 cm apart. At what point on the line joining them the electric field is zero?(a) 15 cm from the charge q (b) 7.5 cm from the charge q(c) 20 cm from the charge 4q (d) 5 cm from the charge q

1.5 A dipole is placed in a uniform electric field with its axis parallel to the field. It experiences(a) Only a net force (b) only a torque(c) both a net force and torque (d) neither a net force nor a torque

1.6 If a point lies at a distance x from the midpoint of the dipole, the electric potential at this point is proportional to(a) 1/x2 (b) 1/x3 (c) 1/x4 (d)1/x 3/2

1.7 Four charges +q, +q, −q and –q respectively are placed at the corners A, B, C and D of a square of side a. The electricpotential at the centre O of the square is

(a)

1

4

q

a (b)

1 2

4

q

a (c)

1 4

4

q

a (d) zero 1.8 Electric potential energy (U) of two point charges is

(a)12

420 (b) (c) pE cos θ (d) pE sin θ

1.9 The work done in moving 500 μC charge between two points on equipotential surface is(a) zero (b) finite positive (c) finite negative (d) infinite

1.10 Which of the following quantities is scalar?(a) dipole moment (b) electric force (c) electric field (d) electric potential

1.11 The unit of permittivity is(a) C2 N−1 m−2 (b) N m2 C−2 (c) H m−1 (d) N C−2 m−2

1.12 The number of electric lines of force originating from a charge of 1 C is(a) 1.129 × 1011 (b) 1.6 × 10−19 (c) 6.25 × 1018 (d) 8.85 × 1012

1.13 The electric field outside the plates of two oppositely charged plane sheets of charge density ζ is

(a)2

(b)

2

(c)

(d) zero

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1.14 The capacitance of a parallel plate capacitor increases from 5 μf to 60 μf when a dielectric is filled betweenthe plates. The dielectric constant of the dielectric is(a) 65 (b) 55 (c) 12 (d) 10

1.15 A hollow metal ball carrying an electric charge produces no electric field at points(a) outside the sphere (b) on its surface (c) inside the sphere (d) at a distance more than twice

PTA QUESTIONS (IMPORTANT )

1) SI unit of electric charge isa) coulomb b) ampere second c) volt second / ohm d) all the above

2) Electric dipole moment always acts in the direction froma) +q to –q b) –q to +q c) infinity to +q d) infinity to –q

3) An electric dipole in a uniform electric field experiencesa) force b) torque c) momentum d) neither force nor torque

4) When a dipole is aligned with field then potential energy is given asa) pE sin θ b) 0 c) –pE d) pE cos θ

5) Relative permittivity of vacuum isa) 3 b) 1 c) 2 d) 0

6) The permittivity of vacuum is ε0 is equal to

a) 14π X 9 X 109 C-2 N+1m+2 b) C2 N-1m-2 c) 9 X 109 C-2 N+1m+2 d) 9 X 109 C2 N-1m-2

7) A lightning conductor works on the principle ofa) Corona discharge b) action of sharp points c) (a) or (b) d) none

8) An electric dipole consists of two -------------------- chargesa) like and equal b) like and unequal c) unlike and equal d) unlike and unequal

9) Action of points is used ina) dynamo b) lightning conductor c) Van de Graff generator d) both (b) and (c)

10) An example for polar moleculea) N2 b) H2 c) H2O d) O2

11) Two charges 10-6 C and 10-7 C repel each other with a force of 400 N. The distance between the charges isa) 0.15 mm b) 1.5 mm c) 15 mm d) 1.5 m

12) If the distance between two protons in uranium atom is 9 X 10-15 m, then the mutual electric potential energybetween thema) 9 X 10-14 J b) 1.44 X 10-15 J c) 2.56 X 10-14 J d) 1.6 X 10-5 J

13) If two identical point charges separated by 3m experience a force of 10 N, then the value of each charge isa) 10-1 C b) 10 C c) 1 C d) 10-4 C

PUBLIC QUESTIONS(V V I )

1) The unit of electric fluxa) Nm2C-1 b) Nm-2C-1 c) Nm2C d) Nm-2C

2) The work done in moving 4 μC charge from one point to another in an electric field is 0.012 J.The potential difference between them is

a) 3000 V b) 6000 V c) 30 V d) 48 X 103

V3) Torque on a dipole in a uniform electric field is maximum when a angle between p and E isa) 0o b) 90o c) 45o d) 180o

4) Potential energy of two equal negative point charges of magnitude 2 μC placed one meter apart in air isa) 2 J b) 0.36 J c) 4 J d) 0.036 J

5) The value of permittivity of free space is

a) 8.854 X 1012 C2 N-1m-2 b) 9X 109 C2 N-1m-2 c) 1 / 9 X 109 C2 N-1m-2 d)

C2N-1m-2 6) The principle used in lightning conductor is

a) corona discharge b) mutual induction c) self induction d) electromagnetic induction7) The unit of electric field intensity is

a) N C-2 b) N C c) V m-1 d) V m8) The unit of electric dipole moment is

a) V / m b) C / m c) V m d) C m 9) Electric potential energy of an electric dipole in electric field is given by

a) pE sinθ b) - pE sinθ c) -pE cosθ d) pE cosθ

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10) Which of the following is not a dielectric?a) ebonite b) mica c) oil d) gold

11) In the given circuit the effective capacitance between A and B will be

a) 3 μF b) 36 / 13 μF c) 13 μF d) 7 μF12) The direction of electric field at a point on the equatorial line due to an electric dipole is

a) along the equatorial line towards the dipole b) along the equatorial line away from the dipolec) parallel to the axis of the dipole and opposite to the direction of dipole momentd) parallel to the axis of the dipole and in the direction of dipole moment

13) The number of electric lines of force originating from a charge of 1 μC isa) 1.129 X 105 b) 1.6 X 10-19 c) 6.25 X 1018 d) 8.85 X 10-12

14) The equivalent capacitance of two capacitors in series is 1.5 μF. The capacitance of one of them is 4 μF. The value ofcapacitance of the other isa) 2.4 μF b) 0.24 μF c) 0.417 μF d) 4.17 μF

15) The law that governs the force between electric charges isa) Ampere‟s law b) Faraday‟s law c) Coulomb’s law d) Ohm‟s law 16) An electric dipole placed at an angle in a non – uniform electric field experiences

a) neither a force nor a torque b) torque only c) both force and torque d) force only17) A capacitor of capacitance 6 μF is connected to a 100 V battery. The energy stored in a capacitor

a) 30 J b) 3 J c) 0.03 J d) 0.06 J18) When an electric dipole of dipole moment p is aligned parallel to the electric field E then the potential; energy of the dipole

is given asa) pE b) zero c) –pE d) pE / √ 2

19) Quantization of electric charge is given bya) q = ne b) q = CV c) q = e / n d) q = C / V

20) An example of conductor is

a) glass b) human body c) dry wood d) ebonite21) The unit of electric field intensity is

a) N C b) N C-1 c) V m d) N C-2 22) The magnitude of the force acting on a charge of 2 X 10-10 C placed in a uniform electric field of 10 Vm-1 is

a) 2 X 10-9 N b) 4 X 10-9 N c) 2 X 10-10 N d) 4 X 10-10 N23) The torque experienced by an electric dipole placed in a uniform electric field at an angle θ with the field is

a) pE cosθ b) –pE cosθ c) pE sinθ d) 2pE sinθ 24) The capacitance of a parallel plate capacitor increases from 5 μF to 50 μF when a dielectric is filled between the plates.

The permittivity of the dielectric isa) 8.854 X 10-12 C2 N-1m-2 b) 8.854 X 10-11 C2 N-1m-2 c) 12 d) 10

25) The negative gradient of potential isa) electric force b) torque c) electric current d) electric field intensity

26) When a point charge of 6 μC is moved between two points in an electric field, the work done is 1.8 X 10 -5 J. The potentialdifference between two points isa) 1.08 V b) 1.08 μV c) 3 V d) 30 V

27) Three capacitors of capacitances 1 μF, 2 μF and 3 μF are connected in series. The effective capacitance of the capacitorsisa) 6 μF b) 11 / 6 μF c) 6 / 11 μF d) 1 / 6 μF

28) An electric dipole of moment p is placed in uniform electric field of intensity E at an angle θ with respect to the field. Thedirection of the torque isa) along the direction of p b) opposite to the direction of pc) along the direction of E d) perpendicular to the plane containing p and E

29) The electric field intensity at a distance r due to infinitely long straight charged wire is directly proportional to

a) r b) 1 / r c) r 2

d) 1 / r 2

30) The ratio of electric potential at points 10 cm and 20 cm from the centre of an electric dipole along its axial line isa) 1 : 2 b) 2 : 1 c) 1 : 4 d) 4 : 1

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31) The intensity of electric field at a point is equal toa) the force experienced by a charge qb) the work done in bringing unit positive charge from infinity to that pointc) the positive gradient of the potential d) the negative gradient of the potential

32) The capacitance of a capacitor isa) directly proportional to the charge q given to it b) inversely proportional to its potential Vc) directly proportional to the charge q and inversely proportional to the potential V

d) independent of both the charge q and potential V33) The intensity of the electric field that produces a force of 10-5 N on a charge of 5 μC isa) 5 X 10-11 NC-1 b) 50 NC-1 c) 2 NC-1 d) 0.5 NC-1

34) The unit of the number of electric lines of force passing through a given area isa) no unit b) NC-1 c) Nm2C-1 d) Nm

35) A dielectric medium is placed in an electric field Eo . The field induced inside the mediuma) acts in the direction of the electric field Eo b) acts opposite to Eo c) acts perpendicular to Eo d) is zero

36) A non – polar dielectric is placed in an electric field ( E ). Its induced dipole momenta) is zero b) acts in the direction of Ec) acts opposite to the direction of E d) acts perpendicular to E

37) n capacitors each of capacitance C are connected in series. The effective capacitance is

a) n / C b) C / n c) nC d) C38) When the charge given to a capacitor is doubled, its capacitancea) increases twice b) decreases twice c) increases four times d) does not change

39) The value of relative permittivity of air isa) 8.854 X 10-12 C2N-1m-2 b) 9 X 109 C2N-1m-2 c) 1 d) 8.854 X 1012

40) The unit of relative permittivity isa) C2N-1m-2 b) Nm2C-2 c) no unit d) NC-2m-2

41) The electric field intensity at a short distance r from uniformly charged infinite plane sheet of charge isa) proportional to r b) proportional to 1 / r c) proportional to 1 / r 2 d) independent of r

42) Two point charges +q and -q are placed at points A and B respectively separated by a small distance. The electric fieldintensity at the midpoint O of AB

a) is zero b) acts along AB c) acts along BA d) acts perpendicular to AB43) An electric dipole of dipole moment „p‟ is kept parallel to an electric field intensity „E‟. The work done in rotating the dipolethrough an angle of 90 isa) zero b) –pE c) pE d) 2pE

44) The total flux over a closed surface enclosing a charge q ( in Nm2C-1)a) 8πq b) 9 X 109 q c) 36π X109 q d) 8.854 X 10-12 q

45) The repulsive force between two like charges of 1 coulomb each separated by a distance of 1m in vacuum is equal toa) 9 X 109 N b)109 N c) 9 X 10-9 N d) 9 N

ADDITIONAL QUESTIONS

1) Two capacitors of 20 F and 35 F are charged to a potential of 120 V each. When they are connected in parallel, thepotential across them isa) 60 V each b)100 V each c) 120 V each d) 240 V each

2) The component used in tuning the radio circuit isa)resistors b) capacitors c) transistors d) diodes3) The equivalent capacitance of (n + 1 ) identical capacitors connected in series is

a) (n + 1 ) C b) 1 / (n + 1) C c) (n + 1) / C d) C / (n + 1) 4) In a hydrogen atom, the electron and proton are bound together at a separation of about 0.53 Ǻ. If the potential energy is

zero at infinite separation, then the potential energy of the electron proton system is ____________a) –54. 4 eV b) –27.2 eV c) –13.6 eV d) zero

5) The meaning of the Greek word electron is ______________a) electricity b) Charge c) amber d) glass

6) The property of attraction and repulsion between charged bodies is not used in ________a) fly – ash collection in Chimneys b) ink – jet printing c) Xerox machine d)Cordless phone

7) The electric field inside an electrostatic shielding is ____________

a) E = 0 b) infinity c) E = q / 40 r 2 d) q / 40 R28) The angle between the direction of electric field and an equipotential surface is ________

a)zero b)900 c) 1800 d) 600

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9) The induced dipole moment is given as ______________a) P = E b) P = / E c) P = E d) P =

10) The working principle of Van de Graff generator is ____________a)action of points b) electrostatic inductionc) action of points and electrostatic induction d) None of these

11) If the distance between two charges is doubled the electrostatic force between the charges will be _____________a)four times more b) four times less c) will increase two times d) will decrease two times

12) If a proton is moved against the coulomb force of an electric field __________a) work is done by the electric field b)energy is used from some outside source c) the strength of the field is decreased d) the energy of the system is decreased

13) If two capacitors of capacitance 2 F and 6 F are put in series, the effective capacitance of the system is

a) 8 F b) 2 F c) F d)

2

3F

14) The tangent to the electric line of force at any point gives ____________a)the potential at that point b) the strength of electric fieldc)the direction electric field at that point d) magnetic line

15) The electric potential at infinity from a point charge q is ______________a)zero b)infinity c) 2q d) q/2

16) The potential energy of a system of charges 3C and 3C separated by a distance of 9 m is ________

a) 3 x 109

Joules b) 9 x 109

Joules c)27 x 109

Joules d) 1/9 x 109

Joules17) The electric potential at any point on the equatorial line of a dipole is _________a)zero b)infinity c) P/40 r d) P / 40 r 3

18) In a circular plate the charges accumulate at __________a)the center b) at the surface area c) at the edges d)entire surface including edges.

19) The working principle of electrophorus is ____________a) Self induction b) Mutual induction c) electrostatic induction d) electromagnetic induction

20) The total flux over a closed surface enclosing a charge q is __________a) 9 x 109 q b) 4q c) 36 q d) 36 x 109 q

21) The work done in moving a unit +ve charge in a uniform electric field is ____________a)infinity b) maximum c) minimum d) zero

22) The electric potential at a point due to a charge of 100 micro coulomb at a distance of 9 metres is ____________

a) 9 V b) 100 V c) 100 micro volt d) 10 5 V

THREE MARKSV V I1) State Coulomb‟s law in electrostatics 2)Define 1 coulomb on the basis of Coulomb‟s law 3) Define electric field intensity. Give its unit 4)What is an electric dipole? Define electric dipole moment5) Define electric flux. Give its unit 6) Why is safer to be inside a car than standing under a tree during lightning?7) State Gauss law in electrostatics 8) What are the applications of capacitor?9) Distinguish between electric potential and potential difference

IMPORTANT

1) Define the unit of potential difference 2) What is an equipotential surface?3) What is electrostatic induction? 4) What is a capacitor? Define its capacitance5) Define the unit of capacitance 6) What is meant by dielectric polarization?7) What is polar molecule? Give two examples 8) What is non - polar molecule? Give two examples

ADDITIONAL

1) Distinguish between conductors and insulators. Give examples2) What is permittivity and relative permittivity? How are they related?3) What does an electric dipole experience when kept in uniform electric field and non- uniform electric field?4) Write a note on microwave oven

PUBLIC PROBLEMS (IMPORTANT)

1) Three capacitors each of capacitance 9 pF are connected in series. What is the total capacitance of the combination?

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2) Calculate the effective capacitance of the combination shown in the figure

3) Calculate the potential at a point due to a charge of 4 X 10-7 C located at 0.09 m away from it

FIVE MARKSV V I

1) Obtain an expression for electric field at a point due to a point charge2) Write the properties of electric lines of force3) Derive an expression for the torque acting on the electric dipole when placed in the electric field4) Obtain an expression for the electric potential due to point charge5) Deduce the expression for the capacitance of the parallel plate capacitor6) Prove that the energy stored in parallel plate capacitors is q2 / 2C

IMPORTANT

1) Obtain an expression for the electric potential energy of an electric dipole in an electric field2) Obtain an expression for electrostatic potential energy for the system of two point charges

ADDITIONAL

1) What is a dielectric? Explain the effect of introducing a dielectric slab between the plates of parallel plate capacitor

PUBLIC PROBLEMS(IMPORTANT )

1) A parallel plate capacitor has plates of area 200 cm2 and separation between the plates is 1 mm. Calculate(i) the potential difference between the plates if 1 nC charge is given to the capacitor. (Ii) With the same charge if the plateseparation is increased to 2 mm, what is the new potential difference and (iii) the electric field between the plates?

2) Three capacitors each of capacitance 9 pF are connected in series. (i) What is the total capacitance of the combination?(ii) what is the potential difference across each capacitor if the combination is connected to 120 Vsupply ?

3) Two capacitors of capacitances 0.5 μF and 0.75 μF are connected in parallel and the combination to a 110 V battery. Calculate the charge from the source and charge on each capacitor4) A square of side 1.3 m has charges + 12 nC, - 24 nC, + 31 nC and + 17 nC as its corners. Calculate the electric

potential at the centre of the square5) Two positive charges of 12 μC and 8 μC respectively are 10 cm apart. Find the work done in bringing those 4 cm

closer, so that they are 6 cm apart6) Two capacitors of unknown capacitances are connected in series and parallel. If the net capacitances in the

two combinations are 6 μF and 25 μF respectively. Find their capacitances7) The plates of the parallel plate capacitor have an area of 90 cm2 each and are separated by 2.5 mm.The capacitor is charged by connecting it to a 400 V supply. How much electrostatic energy is stored by the capacitor?

8) Three charges - 2 X 10-9 C, + 3 X 10-9 C and – 4 X 10-9 C are placed at the vertices of an equilateral triangle ABC of side20 cm. Calculate the work done in shifting the charges from A , B and C to A1, B1 and C1 respectively. Which are the mid – points of the sides of triangle?

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TEN MARKSV V I

1) What is an electric dipole? Derive an expression for the electric field due to an electric dipole at a point on its axial line2) Derive an expression for the electric field due to an electric dipole at a point on its equatorial line3) Derive an expression for the electric potential due to electric dipole. Discuss the possible cases4) State the principle and explain the construction and working of Van de Graaff generator

5) Deduce the expression for the equivalent capacitance of capacitors connected in series and parallel6) State Gauss‟s law. Applying this, calculate electric field due to i) an infinitely long straight charged wire with uniformcharge density ii) an infinite plane sheet of charge

ADDITIONAL

1) Explain the principle of capacitor. Deduce an expression for the capacitance of the parallel plate capacitor.

Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω

2. CURRENT ELECTRICITY

ONE MARKS – BOOK BACK( V V I )

2.1 A charge of 60 C passes through an electric lamp in 2 minutes. Then the current in the lamp is(a) 30 A (b) 1 A (c) 0.5 A (d) 5 A

2.2 The material through which electric charge can flow easily is(a) quartz (b) mica (c) germanium (d) copper

2.3 The current flowing in a conductor is proportional to(a) drift velocity (b) 1/ area of cross section(c) 1/no of electrons (d) square of area of cross section.

2.4 A toaster operating at 240V has a resistance of 120Ω. The power is(a) 400 W (b) 2 W (c) 480 W (d) 240 W2.5 If the length of a copper wire has a certain resistance R, then on doubling the length its specific resistance

(a) will be doubled (b) will become 1/4th (c) will become 4 times (d) will remain the same.2.6 When two 2Ω resistances are in parallel, the effective resistance is

(a) 2 Ω (b) 4 Ω (c) 1 Ω (d) 0.5 Ω 2.7 In the case of insulators, as the temperature decreases, resistivity

(a) decreases (b) increases (c) remains constant (d) becomes zero2.8 If the resistance of a coil is 2 Ω at 0oc and α = 0.004 /oC, then its resistance at 100o C is

(a) 1.4 Ω (b) 0 Ω (c) 4 Ω (d) 2.8 Ω 2.9 According to Faraday‟s law of electrolysis, when a current is passed, the mass of ions deposited at the cathode is

independent of(a) current (b) charge (c) time (d) resistance 2.10 When n resistors of equal resistances (R) are connected in series, the effective resistance is

(a) n/R (b) R/n (c) 1/nR (d) nR

PTA QUESTIONS(IMPORTANT)

1) The external energy necessary to drive the free electrons in a definite direction is calleda) current b) resistance c) emf d) power

2) Force experienced by a free electron in an electric field „E‟ is a) Ee b) E / e c) e / E d) Ee2

3) The unit of mobility isa) m2V1s-1 b) m2V-1s-1 c) m-2V-1s-1 d) m2V-1s-2

4) Drift velocity of electrons is of the order ofa) 0.2 cm s-1 b) 0.1 cm s-1 c) 0.1 m s-1 d) 1 cm s-1

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5) The unit of conductance isa) ohm m-1 b) mho m c) ohm m d) mho

6) The unit of resistivity isa) ohm m-1 b) mho m c) ohm m d) mho

7) Resistivity of mercury is zero ata) 2.4 K b) 4.2 oC c) 4 .2 K d) 2.4 oC

8) At the transition temperature the electrical conductivity becomes

a) zero b) infinity c) minimum d) none of these9) The tolerance carbon resistors without a colour ring isa) 20 % b) 10 % c) 2 % d) 25 %

10) If the resistance of a material increases with increase in temperature then its temperature coefficient of resistancea) zero b) negative c) positive d) none of these

11) A material with negative temperature coefficient of resistance is calleda) metal b) alloy c) thermistor d) thermometer

12) Due to ageing, the internal resistance of a cell isa) increases b) decreases c) doesn‟t change d) becomes zero

13) One kilo watt hour is equal toa) 3.6 X 105 J b) 0.36 X 105 J c) 36 X 105 J d) 36 X 103 J

14) Unit of electrochemical equivalent is

a) C kg-1 b) kg C c) kg C-2 d) kg C-1 15) Electrolyte used in lead – acid accumulator isa) lead acid b) HCl c) dil. H2SO4 d) HNO3

16) The number of electrons flowing per second through a conductor, when a current of 3.2 A flows through it isa) 2 X 1019 b) 3 X 1018 c) 6.25 X 1018 d) 6.25 X 1019

17) A 750 W power iron box is used for 4 hours. If the cost per unit is 75 paise, the total expense isa) Rs. 22.50 b) Rs. 5.25 c) Rs.2.25 d) Rs.3.00

18) The value of carbon resistor with the colour code of yellow, violet and orange isa) 37 k Ω b) 4.7 k Ω c) 47 k Ω d) 3.7 k Ω

PUBLIC QUESTIONS( V V I )

1) Resistance of a metal wire of length 10 cm is 2 Ω. If the wire is stretched uniformly to 50 cm, the resistance isa) 25 Ω b) 10 Ω c) 5 Ω d) 50 Ω

2) The colour code on a carbon resistor is red – red – black. The resistance of the resistor isa) 2.2 Ω b) 22 Ω c) 220 Ω d) 2.2 kΩ

3) The brown ring at one end of a carbon resistor indicates a tolerancea) 1 % b) 2 % c) 5 % d) 10 %

4) The unit of conductivity isa) mho b) ohm c) ohm – m d) mho – m-1

5) The transition temperature of mercury isa) 4.2 oC b) 4.2 K c) 2.4 oC d) 2.4 K

6) The relation between current and drift velocity is

a) I = n A Vd / e b) I = n A Vd e c) I = n e Vd / A d) I = n A Vd E7) When the diameter of a conductor is doubled, its resistancea) decreases twice b) decreases four times c) decreases sixteen times d) increases four times

8) A cell of emf 2.2 V sends a current of 0.2 A through a resistance of 10 Ω. The internal resistance of the cell isa) 0.1 Ω b) 1 Ω c) 2 Ω d) 1.33 Ω

9) The electrical resistivity of a thin copper wire and a thick copper rod are respectively ρ1Ω m and ρ2Ω m. Then

a)ρ1>ρ2 b) ρ2 > ρ1 c) ρ1= ρ2 d)ρ1 /ρ2 = ∞


1) The value of the carbon resistor whose colours are red, green, yellow is ________a) 250 b) 230 c) 230 K d) 250 K

2) The amount of charge in a metallic wire is 5 x 107C. If the current density in the wire is 3 x 105 C ,the drift velocity of the electron is ____________a) 1.67 x 102 ms-1 b) 6 x 10 3 ms-1 c) 6 x 10 -3 ms-1 d) 3 x 10 13 ms-1

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3) The potential developed between two ends of conductor is 25 volts. 2A current flows through it.The conductance of the conductor is ____________a) 80 mho b) 80 milli mho c) 80 micro mho d) 40 mho

4) A resistance wire is cut into 4 equal parts and all the four parts are connected in parallel.The ratio of the effective resistance to the original resistance is ________a) 1 : 2 b) 2 : 1 c) 4 : 1 d) 1 : 4

5) The resistance of a conductor is 5 at 500 C and 6 at 1000 C. Then the resistance at 00 C is ____________

a) 0 b) 3.5 c) 4 d) 8 6) The current always flow from _________a) Positive to negative b) Negative to positivec) Zero potential to zero potential d) Positive to positive

7) The external energy necessary to drive the electrons in a definite direction is called _____a) Force b) Electromotive force c) Potential difference d) Current

8) The current i is expressed as ___________a)i = q x t b) i = q / t c) i = t / q d) i = 1 / qt

9) Ohm‟s law is true only when _____________ a)temperature increases b) temperature decreasesc)temperature neither increases nor decreases d) temperature increases and decreases

10) The conductivity of super conductors is ____________

a)zero b) very low c) infinity d) very high11) The super conducting transition temperature of mercury is _______________

a) 4.20C b) 268.80C c) -268.80C d) 00C12) Current in a super conducting wire can flow __________

a)without change in magnitude b) without change in magnitude and directionc)with the change in magnitude d) with the change in energy

13) The silver or gold ring on a carbon resistor corresponds to ________a)first number b) second number c) powers of 10 d) tolerance

14) The grey colour ring on a carbon resistor corresponds to ___________________a)1 b) 2 c) 9 d) 8

15) The blue colour ring on a carbon resistor corresponds to ________________a) 4 b) 3 c) 5 d) 6

16) The tolerance of silver ring is _____________a) 1% b) 2% c) 5% d) 10%

17) In the parallel combination of resistors ___________ is the same.a)current b) potential difference c) resistance d) all the three

18) Thermistor is a material with ___________ temperature coefficient of resistancea)low and +ve b) high and +ve c) negative d)

19) The bridge wire in metre bridge is made up of __________a) Steel b) Copper c) Nichrome d) Manganin

20) The emf is ______________a.

directly proportional to the resistance in the external circuitb. inversely proportional to the resistance in the external circuit

c.

independent of the resistance in the external circuitd.

is a force21) The instrument used to measure electric power is _______________________

a) Ammeter b) Multimeter c) Wattmeter d) Voltmeter22) Mass of the substance liberated at an electrode during electrolysis is ___________

a)m = z i2 t b) m = z2 i t c) m = z i t d) m = z i t2 23) Primary cell is a device which converts ____________

a)electrical energy into chemical energy b) chemical energy into electrical energyc)chemical energy into kinetic energy d) heat energy into electrical energy

24) The anode in Daniel cell is ____________a)zinc rod b) copper rod c) copper vessel d) glass vessel

25) The anode in Lechlanche cell is ____________

a)zinc rod b) copper electrode c) copper vessel d) carbon rod 26) The current from Lechanche cell is ____________________a) 1 A b) 0.5 A c) 2 A d) 0.25 A

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27) The cathode in Lead acid accumulator is _______________a) PbO2 b) spongy – lead c) carbon plate d) copper plate

28) The specific gravity of the electrolyte in Lead – Acid accumulator __________a) 1.2 b) 1.284 c) 1.28 d)1.82

THREE MARKS

V V I

1) Define drift velocity. Give its unit 2)Define mobility of electrons. Give its unit3) Define current density. Give its unit 4)State Ohm‟s law 5) Name three changes observed in transition temperature 6)State Kirchoff‟s first law 7) State Kirchoff‟s second law 8) Distinguish between electric power and electric energy9) State Faraday‟s laws of electrolysis 10) Distinguish between emf and potential difference11) Define temperature co - efficient of resistance 12) Mention any three applications of secondary cells

IMPORTANT

1) Define resistivity of a material. Give its unit 2) Define critical temperature in superconductors3) Define electric current. Give its unit 4) Why is copper wire not suitable for potentiometer?

ADDITIONAL

1) Distinguish between primary cells and secondary cells2) Why automobile batteries have low internal resistance.3) The colours of carbon resistor are orange, orange, orange. What is the value of resistor?

PUBLIC PROBLEMS(IMPORTANT)

1) In the following circuit, calculate the current through the circuit. Mention its direction

2) A manganin wire of length 2 m has a diameter of 0.4 mm with a resistance of 70 Ω. Find the resistivity of the material3) Three resistors are connected in series with 10 V supply as shown in the figure. Find the voltage drop across each

resistor

4) The resistance of a platinum wire at 0 oC is 4 Ω. What will be the resistance of the wire at 100 oC if the temperaturecoefficient of resistance of platinum is 0.0038 /oC

5) The resistance of a nichrome wire at 0 oC is 10 Ω. If is temperature coefficient of resistance is 0.004 /oC, find its resistanceat boiling point of water. Comment on the result

6) Two wires of small material and length have resistances 5 Ω and 10 Ω respectively. Find the ratio of radii of two wires7) If 6.25 X 1018 electrons flow through a given cross section of a conductor in unit time, find the current

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8) In the given circuit what are the total resistance and current supplied by the battery?

9) Find the magnitude and direction of the current in the following circuit

10) From the following network find the effective resistance between A and B

FIVE MARKS( V V I )

1) Distinguish between drift velocity and mobility. Establish a relation between drift velocity and current2) List some applications of superconductors3) Explain the effective resistance of a series network4) Explain the effective resistance of a parallel network5) Explain the determination of internal resistance of a cell using voltmeter6) Obtain the condition for zero deflection in Wheat stone‟s network 7) State and verify Faraday‟s first law of electrolysis 8) State and verify Faraday‟s second law of electrolysis

IMPORTANT

1) Explain the principle of a potentiometer.2) How can emf of two cells be compared using potentiometer?3) Explain the reactions at the electrodes of Daniel cell4) Explain the reactions at the electrodes of Leclanche cell5) Explain the flow of charges in metallic conductor

ADDITIONAL

1) Describe an experiment to find unknown resistance and temperature coefficient of resistance using meter Bridge2) Explain the action of the lead acid accumulator


1) In the given network calculate the effective resistance between points A & B

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2) The effective resistances are 10 Ω, 2.4 Ω when they are connected in series and parallel respectively. What are theresistances of individual resistors?

3) A copper wire of 10-6 m2 area of cross section, carries a current of 2 A. If the number of electrons per cubic meter is8 X 1028. Calculate the current density and average drift velocity.

4) Three resistors are connected in series with 10 V supply as shown in the figure. Find the voltage drop across each other

5) What is the drift velocity of an electron in a copper conductor having area 10 X 10-6 m2, carrying a current of 2 A. Assumethat there are 10 X 1028 electrons / m3

6) Find the current flowing across three resistors 3 Ω, 5 Ω, and 2 Ω connected in parallel to a 15 V supply. Also find theeffective resistance and total current drawn from the supply.

7) In a meter bridge, the balancing length for a 10 Ω resistance in left gap is 51.8 cm. Find the unknown resistance andspecific resistance of a wire of length 108 cm and radius 0.2 mm.

8) An iron box of power 400 W is used daily for 30 minutes. If the cost per unit is 75 paise, find the weekly expense on usingthe iron box

9) The resistance of a field coil measures 50 Ω at 20°C and 65 Ω at70°C. Find the temperature coefficient of resistance.Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω

3. EFFECTS OF ELECTRIC CURRENT

ONE MARKS – BOOK BACK (V V I )

3.1 Joule‟s law of heating is

(a) H =I2

R t (b) H = V2 Rt (c) H = VIt (d) H = IR2t

3.2 Nichrome wire is used as the heating element because it has

(a) low specific resistance (b) low melting point (c) high specific resistance (d) high conductivity3.3 Peltier coefficient at a junction of a thermocouple depends on

(a) the current in the thermocouple (b) the time for which current flows(c ) the temperature of the junction (d) the charge that passes through the thermocouple

3.4 In a thermocouple, the temperature of the cold junction is 20oC, the neutral temperature is 270ºC.The temperature of inversion is(a) 520ºC (b) 540ºC (c) 500ºC (d) 510ºC

3.5 Which of the following equations represents Biot-savart law?

(a) = 04

2 (b) = 04 2 (c) = 04

2 (d) =

3.6 Magnetic induction due to an infinitely long straight conductor placed in a medium of permeability μ is

(a)

μ0 I4πa (b)

μ0 I2πa (c)

μ I4πa (d)

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3.7 In a tangent galvanometer, for a constant current, the deflection is 30o. The plane of the coil is rotated through 900. Now,for the same current, the deflection will be(a) 300 (b) 600 (c) 900 (d) 00

3.8 The period of revolution of a charged particle inside a cyclotron does not depend on(a) the magnetic induction (b) the charge of the particle(c) the velocity of the particle (d) the mass of the particle

3.9 The torque on a rectangular coil placed in a uniform magnetic field is large, when

(a) the number of turns is large (b) the number of turns is less(c) the plane of the coil is perpendicular to the field (d) the area of the coil is small3.10 Phosphor – bronze wire is used for suspension in a moving coil galvanometer, because it has

(a) high conductivity (b) high resistivity`(c) large couple per unit twist (d) small couple per unit twist

3.11 Of the following devices, which has small resistance?(a) moving coil galvanometer (b) ammeter of range 0 – 1A(c) ammeter of range 0 –10 A (d) voltmeter

3.12 A galvanometer of resistance G Ω is shunted with S Ω .The effective resistance of the combination is Ra.Then, which of the following statements is true?(a) G is less than S (b) S is less than Ra but greater than G.(c) Ra is less than both G and S (d) S is less than both G and Ra

3.13 An ideal voltmeter has(a) zero resistance (b) finite resistance less than G but greater than Zero(c) resistance greater than G but less than infinity (d) infinite resistance

PTA QUESTIONS(IMPORTANT )

1.

Nicrome is used as the heating element, because ----------(a) it has high specific resistance (b) it has high melting point c) it is not easily oxidized (d) all the above

2 . Fuse wire is an alloy of ---------------(a) 37%Pb & 63% Sn (b) 63%Pb & 36% Sn (c) 73Pb & 27% Sn (d) 37%Sb & 63% Sn

3. Melting point of tungsten is----------------(a)3380◦C (b) 3380 K (c) 380◦C (d) 380 K

4. Filament of an electrical bulb is usually enclosed in a glass bulb containing --------(a) inert gas at high pressure (b) inert gas at low pressure(c) ideal gas at high pressure (d) ideal gas at low pressure

5. In which of the following, Joule heating effect is undesirable?(a)electric iron (b) electric toaster (c) transformer and dynamos (d) fuse wire

6. Which of the following is not a thermo emf effect?(a) Peltier effect (b) Thomson effect (c) Joule effect (d) Seebeck effect

7. In a Cu-Fe thermocouple, the direction of the current at the hot junction is---------(a) from Cu to Fe (b) from Fe to Cu(c) either (a) or (b) depending on temperature of hot junction (d) random direction

8. For a given thermocouple, the neutral temperature is -----------(a) maximum (b) minimum (c) zero (d) a constant

9. Electric filament lamp is working on the basis of -------(a) Joule heating effect (b) Peltier effect (c) Thomson effect (d) Seebeck effect

10. An example for positive Thomson metal is-----------(a) iron (b) cobalt (c) copper (d) nickel

11. The device thermopile is based on------------(a) Joule effect (b) Peltier effect (c) Thomson effect (d) Seebeck effect

12. In a thermopile, the deflection in the galvanometer is proportional to -----------(a) intensity (b) frequency (c) velocity (d) energy

13. Magnitude and direction of Lorentz force is given by the expression

a) F =v(q x B ) (b) =q( x ) (c) F =B(v x B ) (d) F =v2(q x B ) 14. An electron is moving with a velocity of 3 x106m / s perpendicular to the magnetic field of 0.5T, and then the force

experienced by the electron is(a) 24 x 10-11N (b) 2.4 x 10-13N (c) 13.6 x 10-27N (d) 13.6 x 10-11N

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15. An α particle with (e/m) ratio 4.8 x 10 7CKg-1 travels in a circular path of radius 0.45m in a magnetic field of 1.2 T,then the speed of the α particle is (a) 2.6 x 104m/s (b) 2.6 x 105m/s (c) 2.6 x 107m/s d) 1.3 x 107m/s

16. Period of revolution of a charged particle inside a cyclotron does not depend on(a) the magnetic induction (b) the charge of the particle(c) the velocity of the particle (d) the mass of the particle

17. Work done by a Lorentz force is

(a) zero whenθ

= 90◦

(b) zero whenθ

= 45◦

(c)always zero (d) maximumθ

= 90◦

18. Two parallel straight conductors carrying currents in the same direction(a) repel each other (b) attract each other (c) do not experience any force (d) experience a maximum force

19. Direction of a force acting on a current carrying conductor placed in a magnetic field is given by(a) Flemings left hand rule (b) Flemings right hand rule (c) end rule (d) Ampere-circuital law

20. A current of 2A flows through two long straight parallel conductors separated by a distance of 10cm.The force per unit length on each conductor is(a) 0.0458 N (b) 8 x 10-4N (c) 8 x 10-5N (d) 8 x 10-6N

21. The coil in moving coil galvanometer is suspended by a(a) aluminium wire (b) copper wire (c) iron wire (d) phosphor-bronze wire

22. Suspended coil galvanometer can measure current of the order of

(a) 10-6A (b) 10-8A (c) 106A (d) 108A23. An ideal ammeter is one which has(a) zero resistance (b) high resistance (c) high resistance in parallel (d) high resistance in series

24. Phosphour-bronze wire is used for suspension in a moving coil galvanometer, because it has(a) high conductivity (b) high resistivity (c) large couple per unit twist (d) small couple per unit twist

25. A galvanometer of resistance of 50 ohm is shunted with a wire of 10 ohm. The current through the galvanometer when thecurrent in the circuit is 12A is(a) 3A (b) 2A (c) 5A (d) 6A

26. The value of gyromagnetic ratio is(a) 8.8 x 109 C/Kg (b) 8.8 x 1010 C/Kg (c) 8.8 x 10-9 C/Kg (d) 8.8 x 10-9 C/Kg

PUBLIC QUESTIONS( V V I) 1) The unit of reduction factor of tangent galvanometer is

a) no unit b) tesla c) ampere d) ampere / degree2) A galvanometer is converted into a voltmeter by connecting a

a) low resistance in series b) high resistance in parallelc) high resistance in series d) low resistance in parallel

3) In a thermocouple, the temperature of the cold junction is 200C, the inversion temperature is 6000C,then the neutral temperature isa) 3100C b) 3200C c) 3000C d) 3150C

4) In a tangent galvanometer a current 1 A, produces a deflection of 300. The current required to produce a deflectionof 600 isa) 3 A b) 2 A c) √3 A d) 1 / √ 3A

5) Peltier effect is the converse ofa) Joule‟s effect b) Raman‟s effect c) Seebeck effect d) Thomson effect6) The torque experienced by a rectangular current loop placed perpendicular to a uniform magnetic field is

a) maximum b) zero c) finite minimum d) infinity7) In which of the following pairs of metals of the thermocouple the e.m.f is maximum?

a) Fe – Cu b) Cu – Zn c) Pt – Ag d) Sb – Bi 8) Which of the following principle is used in a thermopile?

a) Thomson effect b) Peltier effect c) Seebeck effect d) Joule‟s effect 9) Fuse wire is an alloy of

a) Lead and Tin b) Tin and Copper c) Lead and Copper d) Lead and Iron10) Thermopile is used to

a) measure temperature b) measure current c) detect thermal radiation d) measure pressure

11) The resistance of the filament of a 110 W, 220 V electric bulb isa) 440 Ω b) 220 Ω c) 484 Ω d) 848 Ω 12) Unit of Peltier coefficient is

a) ohm b) mho c) volt d) ampere

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13) For a given thermocouple the neutral temperaturea) depends upon the temperature of cold junction b) depends upon the temperature of hot junctionc) is a constant d) depends upon the temperature of cold junction and the temperature of hot junction

14) When the number of turns in a galvanometer is doubled, current sensitivitya) remains constant b) decreases twice c) increases twice d) increases four times

15) An electron is moving with a velocity of 3 X 106 ms-1 perpendicular to a uniform magnetic field of induction 0.5 T.The force experienced by the electron

a) 2.4 X 10-13

N b) 13.6 X 10-27

N c) 13.6 X 10-11

N d) zero16) Fuse wirea) is an alloy of lead and copper b) has low resistancec) has high resistance d) has high melting point

17) In a thermocouple, the temperature of the cold junction is - 300C, and the neutral temperature is 270 0C.The temperature of inversion isa) 5200C b) 5400C c) 5000C d) 570 0C

18) Which of the following produces large Joule heating effect?a) 1 A current through 2 Ω resistor for 3 second b) 1 A current through 3 Ω resistor for 2 secondc) 2 A current through 1 Ω resistor for 2 second d) 3 A current through 1 Ω resistor for 1 second

19) Nicrome is used as the heating element, because it has ----------(a) low specific resistance (b) low melting point c) high specific resistance (d) high conductivity

20) In the experiment to verify Joule‟s law when the current passed through the circuit is doubled keeping resistance ( R ) andtime of passage of current ( t ) constant. Temperature of the liquida) increases twice b) increases four times c) increases sixteen times d) decreases four times

21) AB is rod of lead. The end A is heated. A current I is allowed to flow along AB. Now due to Thomson effect in rod ABa) heat is absorbed b) heat is liberatedc) heat is neither absorbed nor liberated d) heat is first absorbed and then liberated


1) The magnetic induction at the center of a coil of 250 turns, radius 0.25m and carrying a current of 6A is(a) 12

x 10-4 T (b)3.768 x 10-4 T (c)12 x 10-3 T (d)37.68 x 10-3 T2) AT.G. gives a deflection of 45o when a current of 2A flows through it. Then the deflection of 60o produced a current of

(a) 35mA (b) 350 mA (c) 3.7A (d)3.5A 3) When the charge is at rest, then the magnetic Lorentz force is …………..

(a)minimum (b)maximum (c)zero (d)infinity4) Two wires each carrying a current of 600A in the same direction are placed with their axes 0.3 m apart.

The force between them per metre length is ………… (a) 24 N (b)0.24 N (c)240 N (d)2.4N

6) The number of turns of a coil of radius 20 cm required to produce a magnetic field of 5 x 10-4 T at the center with acurrent of 5A is ……………. (a) 50 (b)25 (c) 500 (d) 100

7) The heating element in electric iron is made up of …………… (a)manganin (b)copper (c)steel (d) nichrome

8) In which one of the following the heat production is minimized ?(a)electric iron (b)electric bulb (c)transformer (d)electric oven

9) In a Fe-Cu thermocouple the direction of current is ……… (a)iron to copper at the cold junction (b)iron to copper at the hot junction(c) clockwise (d)anticlock wise

10) Beyond the temperature of inversion the thermo emf …………. (a)invreases (b)changes its sign and increases (c)does not increase (d)neither increases nor decreases

11) The deflection in the galvanometer of a thermopile is proportional to …………. (a)frequency of radiation (b)wavelength of radiation (c)velocity of radiation (d)intensity of radiation

12) The unit of magnetic induction is ………….. (a) Weber (b)Weber –m (c)Weber –m-2 (d)Ampere –m

13) The magnetic polarity of the current carrying solenoid is givent by …………. (a)Fleming‟s left hand rule (b)Maxwell‟s cork screw rule (c)End rule (d)Right hand palm rule

14) If the coil is parallel to the magnetic field the torque is …………(a)zero, (b)minimum (c) maximum (d)infinity

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15) If the number of turns in a galvanometer is doubled ……………….. (a) the current sensitivity is halved (b)the voltage sensitivity is halved(c)voltage sensitivity remain unchanged (d)the voltage sensitivity is doubled

16) Positive charges will always move from ……………….. (a)higher potential to lower poterntial, (b)lower poterntial to higher potential(c)zero poterntial to higher potential (d)zero potential to lower potential

17) In a thermocouple the emf produced at neutral termperature is ……………

(a)zero (b)maximum (c)minimum (d)infinity18) For which of the following Thomson effect is negative ?(a)Sb (b)Zn (c)Co (d)Cu

19) Which law is used to calculate the magnetic induction due to current carrying conductor ?(a)Kirchoff‟s law (b)Gauss law (c)Biot-Savart law (d)Ampere‟s law

20) The working principle of a moving coil galvanometer is …………….. (a) Fleming’s left hand rule (b)Fleming‟s right hand rule (c) Ampere‟s swimming rule (d)Right cork screw rule

21) In a moving coil galvanometer the deflection is …………… (a)directly proportional to the current (b) inversely proportional to the current(c)directly proportional to I2 (d) inversely proportional to I2

22) Shunt is a resistance of …………….

(a) low value connected in a series with galvanometer (b) high value connected in parallel with galvanometer(c) high value connected to series with galvanometer (d) low value connected in parallel with galvanometer23) As the range of voltmeter increases the value of resistance in series ………

(a) increases (b)decreases (c)remains the same (d)becomes zero24) The unit of galvanometer constant

(a) ampere (b) degree (c) ampere / degree (d) no unit

THREE MARKS

V V I

1) State Joule‟s law 2)Why nichrome is used as heating element in heating devices?3) Define Peltier co – efficient. Give its unit 4)Define Thomson co – efficient. Give its unit5) State tangent law 6)What is Ampere‟s circuital law? 7) State Fleming‟s left hand rule 8)Define ampere9) How is galvanometer converted into i) ammeter and ii) voltmeter10) Write the limitations of a cyclotronIMPORTANT

1) How is the current sensitivity of a galvanometer increased?2) State Maxwell‟s right hand cork screw rule 3)State Biot – Savart law

ADDITIONAL

1) In a galvanometer, increasing the current sensitivity does not necessarily increase the voltage sensitivity. Explain2) What is neutral temperature of a thermocouple? 3)Define temperature of inversion4) State end rule


1) Calculate the resistance of the filament of 100 W, 220 V electric bulb.2) A conductor of length 50 cm carrying a current of 5A is placed perpendicular to a magnetic field of induction 2 × 10-3 T.

Find the force on the conductor.FIVE MARKS

V V I

1) State and explain Biot – Savart law.2) Deduce an expression for the magnetic Lorentz force acting on a charged particle3) Explain how will you convert a galvanometer into an ammeter 4) Explain how will you convert a galvanometer into an voltmeter

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ADDITIONAL

1) Explain current loop as a magnetic dipole

PUBLIC PROBLEMS (IMPORTANT )

1) A circular coil of radius 20 cm has 100 turns of wire and it carries a current of 5 A. Find the magnetic induction at appoint

along its axis at a distance of 20 cm from the center of the coil2) A rectangular coil of 500 turns and area 6 X 10-4 m2 is suspended inside a radial magnetic field of induction 10 -4 Tby a

suspension wire of torsional constant 5 X 10-10 Nm per degree. Calculate the current required to produce deflection of 100 3) A moving coil galvanometer of resistance 20 Ω produces full scale deflection for a current of 50 mA. How will you

convert galvanometer into i) an ammeter of range 20 A and ii) a voltmeter of range 120 volt?4) A long straight wire carrying current produces a magnetic induction of 4 X 10-6 T at a point 15 cm from the wire.

Calculate the current through the wire5) In a hydrogen atom electron moves in an orbit of radius 0.5 Ao making 1016 revolutions per second. Determine the

magnetic moment associated with orbital motion of the electron6) Two parallel wires each of length 5 m are placed at a distance of 10 cm apart in air. They carry equal currents alongthe

same direction and experience a mutually attractive force of 3.6 X 10-4 N. Find the current through the conductors.

7) A galvanometer has a resistance of 40 Ω. It shows full scale deflection for a current of 2 mA. How will you convert the galvanometer into a voltmeter of range 0 to 20 V?8) Two straight infinitely long parallel wires carrying equal current placed at a distance of 20 cm apart experience a mutually

attractive force of 4.9 X 10 -5 N per unit length of the wire. Calculate the current9) The deflection of a galvanometer falls from 50 divisions when 12 Ω resistance is connected across the galvanometer.

Calculate the galvanometer resistance. TEN MARKS

V V I

1) State Joule‟s law of heating. Explain Joule‟s calorimeter experiment to verify Joule‟s law2) Deduce an expression for the magnetic induction due to an infinitely long straight conductor carrying current.

Write the expression for the magnetic induction when the conductor is placed in a medium of permeability μ3) Deduce the relation for the magnetic induction at a point along the axis of a circular coil carrying current4) Explain in detail the principle, construction and theory of a tangent galvanometer5) Explain the principle, construction, working and limitations of a cyclotron with a diagram IMPORTANT

1) Applying Ampere‟s circuital law, find the magnetic induction due to a straight solenoid2) Obtain an expression for the force between two long parallel current carrying conductors. Hence define ampere.3) Discuss the motion of a charged particle in a uniform magnetic field ADDITIONAL

1) Explain in detail the principle, construction and theory of moving coil galvanometer

Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω

4. ELECTROMAGNETIC INDUCTION A . C

ONE MARKS – BOOK BACK (V V I )

4.1 Electromagnetic induction is not used in(a) transformer (b) room heater (c) AC generator (d) choke coil

4.2 A coil of area of cross section 0.5 m2 with 10 turns is in a plane which is perpendicular to an uniform magnetic fieldof 0.2 Wb/m2.The flux though the coil is(a) 100 Wb (b) 10 Wb (c) 1 Wb (d) zero

4.3 Lenz‟s law is in accordance with the law of (a) conservation of charges (b) conservation of flux (c) conservation of momentum (d) conservation of energy

4.4 The self −inductance of a straight conductor is(a) zero (b) infinity (c) very large (d) very small

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4.5 The unit henry can also be written as(a) Vs A−1 (b) Wb A−1 (c) Ω s (d) all

4.6 An emf of 12 V is induced when the current in the coil changes at the rate of 40 A S –1. The coefficient of self inductionof the coil is(a) 0.3 H (b) 0.003 H (c) 30 H (d) 4.8 H

4.7 A DC of 5A produces the same heating effect as an AC of(a) 50 A rms current (b) 5 A peak current (c) 5A rms current (d) none of these

4.8 Transformer works on(a) AC only (b) DC only (c) both AC and DC (d) AC more effectively than DC4.9 The part of the AC generator that passes the current from the coil to the external circuit is

(a) field magnet (b) split rings (c) slip rings (d) brushes 4.10 In an AC circuit the applied emf e = Eo sin (ωt + π/2) leads the current I = Io sin (ωt – π/2) by

(a) π/2 (b) π/4 (c) π (d) 04.11 Which of the following cannot be stepped up in a transformer?

(a) input current (b) input voltage (c) input power (d) all4.12 The power loss is less in transmission lines when

(a) voltage is less but current is more (b) both voltage and current are more(c) voltage is more but current is less (d) both voltage and current are less

4.13 Which of the following devices does not allow d.c. to pass through?

(a) resistor (b) capacitor (c) inductor (d) all the above4.14 In an ac circuit(a) the average value of current is zero. (b) the average value of square of current is zero.(c) the average power dissipation is zero. (d) the rms current is 2 time of peak current

PTA QUESTIONS (IMPORTANT )

1. The generator rule is ---------------(a) Fleming‟s left hand rule (b) Fleming’s right hand rule (c) Maxwell‟s right hand cork screw rule (d) Ampere‟s swimming rule

2. The frequency of A.C. for guided rocket is ---------(a) 50 Hz (b) 400 Kz (c) 400 Hz (d) 100 KHz to 100 MHz

3. The Q-factor has values lying between --------for normal frequencies(a) 0 to 10 (b) 10 to 50 (c) 50 to 100 (d) 10 to 100

4. Cores of chokes using low frequency AC circuits are made of --------(a) stelloy (b) mumetal (c) iron (d) aluminium

5. Power loss due to Joule –heating is also called as -------------(a) copper loss (b) Eddy current loss (c) flux leakage (d) Hysteresis loss

6. ---------- transmits large amount of power with low cost and high efficiency(a) two phase alternator (b) three phase alternator (c) single phase alternator (d) none of the above

7. In low power AC dynamos magnetic field is provided by-------------(a) permanent magnets (b) electromagnets (c) horse-shoe magnets (d) cylindrical magnets

8. The average power of an AC is also called -------- of the circuit(a) true power (b) instantaneous power (c) resonant power (d) RMS power

9. In a three phase AC generator, the three coils are inclined at an angle of ---------------(a) 45o (b) 90o (c) 120o (d) 180o

10. For an ideal transformer, efficiency η is--------(a) greater than one (b) less than one (c) equal to one (d)infinity

11. Induction motors are used in----------(a) grinders (b) generators (c) refrigerators (d) fans

12. In a step down transformer, the following condition is satisfied(a) Es > Ep (b) K < 1 (c) Ip > Is (d)Np < Ns

13. Choke coils are commonly seen in ------------(a) incandescent bulbs (b) fluorescent tubes (c) stabilizer circuits (d) radio

14. A circuit will have flat resonance, it the Q value is ------------(a) high (b) infinity (c) low (d) zero15. 400 MW power produced at 15,000 V at Neyveli power station is stepped upto -------- before transmission

(a) 22,000 V (b) 230,000 V (c)110,000 V (d) 20,000 V

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PUBLIC QUESTIONS( VVI )

1) The angle between the area vector A and the plane of the area A isa) π b) 2π c) π / 2 d) zero

2) If the flux associated with a coil varies at the rate of 1 Wb / minute then the induced e.m.f isa) 1 V b)1 / 60 V c) 60V d) 0.60V

3) In an a.c. circuit with an inductor

a) voltage lags current by π / 2 b) voltage an current are in phasec) voltage leads current by π d) current lags voltage by π / 2 4) In L.C.R series a.c. circuit, the phase difference between current ad voltage is 300. The reactance of the circuit is

17.32 Ω. The value of resistance isa) 30 Ω b) 10 Ω c) 17.32 Ω d) 1.732 Ω

5) The unit of henry can also be written asa) V A s-1 b) Wb-1 A c) Ω s d) all of these

6) In a step –up transformer the input voltage is 220V and the output voltage is 11 kV. The ratio of number of turns ofprimary to secondary isa) 50:1 b) 1:50 c) 25:1 d)1:25

7) In an a.c. circuit, the current I= I0 sin (ωt - π / 2 ) lags behind the e.m.f. e = E0 sin (ωt + π / 2 )bya) 0 b) π / 4 c) π / 2 d) π

8) The generator rule isa) Flemings left hand rule b) Flemings right hand rule c) Maxwell‟s right hand corkscrew rule d) Right hand palm rule.

9) In LCR circuit when XL = XC the currenta) is zero b) is in phase with the voltage c) leads the voltage d) lags behind the voltage

10) Transformer works ona) both AC and DC b) AC more effectively than DC c) AC only d) DC only

11) Lenz‟s law is in accordance with the law ofa) conservation of energy b) conservation of chargec) conservation of momentum d) conservation of angular momentum

12) The self-inductance of a straight conductor isa) Zero b) infinity c) very large d) very small

13) In an AC circuit with capacitor only, if it the frequency of the signal is zero, then the capacitive reactance isa) Infinity b) zero c) finite maximum d) finite minimum

14) In step-up transformer the output voltage is 11 kV and the input voltage is 220 V. The ratio of number of turns ofsecondary to primary isa) 20 : 1 b) 22 : 1 c) 50 : 1 d) 1 : 50

15) The generator rule isa) Fleming‟s left hand rule b) Fleming’s right hand rule c) Maxwell‟s right hand cork screw rule d) Ampere‟s swimming rule.

16) The core used in audio frequency choke isa) Iron b) carbon c) lead d) steel

17) The reactance offered by 300 mH Inductor to an AC supply of frequency 50 Hz isa) 1046 Ω b) 94.2 Ω c) 9420 Ω d) 104.6

18) The r.m.s. value of an a.c. voltage with a peak value of 311 V isa) 100 V b) 220 V c) 50 V d) 70.7 V

19) In a transformer, eddy current loss is minimized by usinga) laminated core made of mumetal b) laminated core made of stelloy c) shell type core d) thick copper wires

20) A power of 11, 000 W is transmitted at 220 V. The current through line wires isa) 50 A b) 5 A c) 500 A d) 0.5 A

21) For a DC circuit the value of capacitive reactance ( Xc ) isa) zero b) infinity c) π / 2 d) π

22) The quality factor of an a.c circuit containing a resistance R, inductance L and capacitance C is

a) Q =

1

b) Q =1

c) Q =

d) Q =

1

23) In a three phase AC generator the three coils are fastened rigidly together and are displaced from each other by an anglea) 90o b) 180o c) 120o d) 360o

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24) In RLC series circuit, at resonancea) current is minimum b) impedance is maximumc) circuit is purely inductive d) current is in phase with the voltage

25) A D.C of 5 A produces the same heating effect as ana) 50 A rms current b) 5 A peak current c) 15 A rms current d) none of these

26) In LCR series circuit, at resonancea) impedance is maximum b) current is minimum c) impedance is equal to R d) o = 1 / √ LC

27) The core used in audio frequency chokes isa) iron b) carbon c) lead d) air28) The r.m.s. value of the alternating current flowing through a resistor is 5 A. Its peak value is

a) 3.536 A b) 70.7 A c) 7.07 A d) 7 A29) A coil of area of cross section 0.5 m2 with 10 turns is in a plane which is parallel to an uniform magnetic field of 0.2 Wb/m 2.

The flux though the coil isa) 100 Wb b) 10 Wb c) 1 Wb d) zero

30) In an A.C. circuit average power consumed is 200 W and the apparent power is 300 W. The power factor isa) 1.5 b) 0.66 c) 0.33 d) 1

31) The effective value of alternating current isa) Io / 2 b) Io / √ 2 c) Io√ 2 d) 2 Io

32) A rectangular coil is uniformly rotated in a uniform magnetic field such that the axis of rotation is perpendicular to the

direction of the magnetic field. When the plane of the coil is perpendicular to the magnetic fielda) (i) magnetic flux is maximum, (ii) induced e.m.f. is maximumb) (i) magnetic flux is zero, (ii) induced e.m.f. is zeroc) (i) magnetic flux is maximum, (ii) induced e.m.f. is zerod) (i) magnetic flux is zero, (ii) induced e.m.f. is maximum

33) In LCR series circuit, at resonancea) XL = XC b) XL> XC c) XL< XC d) ω = 1 / LC

34) In an a.c. circuit the voltage leads the current by a phase of π / 2, then the circuit has a) only an inductor b) only a capacitor c) only a resistor d) L, C and R in series

35) When the frequency of an a.c. circuit increases, the capacitance reactance offered by capacitor connected in the circuita) increases b) decreases c) remains the same d) becomes zero

36) The resonant frequency of RLC circuit is o. The inductance is doubled, the capacitance is also doubled. Now the

resonant frequency of the circuit isa) 2 o b) o / 2 c) o / 4 d) o / √ 2

37) The rms value of a.c voltage with peak of 311 V isa) 220 V b) 311 V c) 180 V d) 320 V

38) The co efficient of self – induction of a solenoid is independent ofa) the number of turns in coil b) the area of cross section of the coilc) the length of the coil d) the current passing through the coil

39) The instantaneous emf and current equations of an a.c. circuit are respectively e = 200 sin + 3 and i = 10 sin .

The average power consumed over one complete cycle isa) 2000 W b) 1000 W c) 500 W d) 707 W

40) In a series RLC circuit, the instantaneous values of current and emf arei= I0 sin (ωt - π / 3 ) ande = E0 sin ωtrespectively.The phase difference between current and voltage isa) zero b) 180° c) 60° d) 45°


1) A coil of 50 turns and area of cross-section of 0.1m2 has its axis perpendicular to a magnetic induction of 0.9 wb / m2,then the flux passing the coil is ………… (a)4.5Wb (b)45 Wb (c) 0 (d) 4.5 m Wb

2) The self inductance of a coil is equal to the magnetic flux linkage of the coil, when the current through the coil is(a) 1 A (b) 1 A / S (c) 2 A (d) constant.

3) For d.c.the capacitor offers ………….. (a)infinite resistance (b)zero resistance (c)maximum resistance, (d) minimum resistance.

4) The coefficient of self induction of a coil of 1000 turns which produces a magnetic flux of 0.5 Wb for a constant currentof 2.5 A is ……… (a)4 x 102 H (b)4 x 10 –2 H (c) 2 x 10-2 H (d)2 x 102 H

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5) In a step up transformer the transformer ratio (k) ……………… (a) K = 0 (b) K > 1 (c) K < 2 (d) K = 1

6) In an ideal transformer ……………. (a)Input power = output power (b)input power ≠ output power(c)input power > output power (d)input power < output power

7) For normal frequencies Q factor lies between .. …………….. (a)0 and ∞ (b)10 and 1000 (c)10 and 100 (d)1 and 100

8) AF choke is a coil of …………. (a)large inductance and low resistance (b)large inductance and large resistance(c)low inductance and low resistance (d)low inductance and high resistance

9) Commercially electric power is generated by the method of ………….. (a)chemical action (b)thermo couple (c)electromagnetic induction (d)photo electric effect

10) When steady current flows through one coil the current induced in the adjacent coil is …………. (a)zero (b) minimum (c)zero (d)infinity

11) A motor is a device used to convert ……………… (a)mechanical energy into electric energy (b)electrical energy into mechanical energy (c)chemical energy into mechanical energy (d)electrical energy into magnetic energy

12) Slots are made in copper plate that swings between the poles of a magnet ………. (a)to minimize the speed of swinging (b)to minimize the eddy current loss

(c)to increase the speed of swinging (d)to increase the eddy current13) The motion of the coil in a galvanometer is damped because of the --------------(a)suspension head (b)elasticity of the suspension wire(c)formation of eddy currents (d) restoring torque

14) Large eddy currents are used in …………… (a)galvanometer damping (b)speedometer (c)induction furnace (d)transformer

15) Stepdown transformer is a device which converts ……………. (a)low voltage AC into high voltage a AC (b)high voltage AC into low voltage AC (c)low power AC into high power AC. (d)high power AC into low power AC

16) The efficiency of a transformer is always ……… (a) equal to 1 (b)less than 1 (c)greater than 1 (d)equal to 2

17) The magnetization of the core of a transformer is repeatedly reversed by the alternating magnetic field.

Some energy is wasted due to this. This is known as … (a)copper loss (b)eddy current loss (c)hysteresis loss (d) flux loss18) Hysteresis losses in a transformer can be minimized by …………

(a)using thick wire of the coils (b)having laminated core made up of stelloy(c)using mumetal as core (d)using a shell type of core

19) The phenomenon of resonance is used in ……… (a)Radar (b)Radio (c)Reactor (d)Generator

20) For ordinary domestic consumers the voltage given is ………… (a)250 V (b)440 V (c)200 V (d)230 V

21) The frequency of domestic power supply is ………….. (a)50 Hz (b)100 π Hz (c)500 Hz (d)200 Hz

22) An AC electric main line is denoted by 220 V, 5A. What do they indicate?(a)Peak value (b)RMS value (c)instantaneous value (d)Mean square Value

23) The frequency of DC current is ……………. (a)zero (b)infinity (c) 50 Hz (d)100 Hz

THREE MARKSVVI

1) Define magnetic flux. Give its unit 2)What is electromagnetic induction?3) State Faraday‟s laws of electromagnetic induction 4)State Lenz law5) State Fleming‟s right hand rule 6)Define self inductance. Give its unit

7) Define 1 henry 8)State the methods of producing induced emf9) Distinguish between step-up & step-down transformer 10)Define quality factor11) Define RMS value of a.c

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IMPORTANT

1) Distinguish between self inductance and mutual inductance 2)What is poly phase AC generator?3) Why a d.c. ammeter cannot read a.c. 4)What is inductive reactance? Give its unit5) What is capacitive reactance? Give its unit 6)A capacitor blocks d.c. but allows a.c. why?7) What is resonant frequency in LCR circuit?

ADDITIONAL

1) What happens to the value of current in RLC series circuit, if frequency of the source is increased?2) Define power factor3) Give the practical applications of self induction ( choke coil )4) Discuss the advantages and drawbacks of a.c. over d.c.5) Define mutual inductance. Give its unit6) Define alternating current .Give its expression.

PUBLIC PROBLEMS ( IMPORTANT )

1) Calculate the mutual inductance between two coils when a current of 4 A changing to 8 A in 0.5 s in one coil, induces an

e.m.fof 50 mV in the other coil.2) An aircraft having a wing span of 20.48 m files due north at a speed of 40 ms-1. If the vertical component of earth‟s

magnetic field at the place is 2 x 10-5 T, calculate the e.m.f. induced between the ends of the wings.3) The wings of an aero plane are 10 cm apart. The plane is moving horizontally towards the north at a place where the

vertical component of earth‟s magnetic field is 3 x 10-5 T. Calculate the induced e.m.f. setup between the tips of the wingsif the velocity of the aero plane is 720 km / hr.

4) A coil of area of cross-section0.5 m2 with 10 turns is in a plane perpendicular to a uniform magnetic field of 0.2 Wb / m2.Calculate the flux through the coil.

5) A capacitor of capacitance 2 μF is in an AC circuit of frequency 1000 Hz. If the r.m.s value of the applied e.m.f is 10 V,find the effective current in the circuit.

6) An ideal transformer has transformation ratio 1 : 20. If the input power and primary voltage are 600 mW and 6 VRespectively, find the primary and secondary currents.

7) Calculate the capacitive reactance of a capacitor of capacitance 2 μF in an A.C. circuit of frequency 1000 Hz8) Write the equation of a 25 cycle current sine wave having rms value of 30 A. 9) An e.m.f. of 5 V is induced when the current in the coil changes at the rate of 100 A s-1. Find the co-efficient of self

induction of the coil

FIVE MARKS ( VVI )

1) Obtain an expression for the energy associated with an inductor2) Obtain an expression for the self inductance of a long solenoid3) Obtain an expression for the mutual inductance between two long solenoids4) Explain how an emf can be induced by changing the area enclosed by the coil

5) What are the reasons for various energy losses in transformer? How they can be minimized?IMPORTANT

1) Obtain an expression for RMS value of alternating current2) Obtain an expression for the current flowing in a circuit containing resistance only. Find the phase relationship between

voltage and current3) Derive an expression for the average power in an a.c circuit4) Describe the principle, construction and working of a choke coil

PUBLIC PROBLEM( IMPORTANT )

1) An A.C generator consists of a coil of 10,000 turns and of area 100 cm2. The coil rotates at an angularspeed of 140 r.p.m in a uniform magnetic field of 3.6 X 10-2 T. Find the maximum value of the e.m.f. induced

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TEN MARKSVVI

1) Discuss with theory the method of inducing emf in a coil by changing orientation with respect to the direction of themagnetic field

2) Describe the principle, construction and working of single phase AC generator3) Explain in detail the principle, construction and theory of a transformer. Define its efficiency. Mention the losses

4) A source of alternating emf is connected to a series combination of a resistor R, an inductor L and a capacitor C. Obtainwith the help of a vector diagram and impedance diagram, an expression for i) the effective voltage ii) the impedanceiii) the phase relationship between the current and the voltage

IMPORTANT

1) Obtain an expression for the current flowing in a circuit containing inductance only. Find the phase relationship betweenvoltage and current

2) Obtain an expression for the current flowing in a circuit containing capacitance only. Find the phase relationship betweenvoltage and current

ADDITIONAL

1) Describe the principle, construction and working of three phase AC generatorΩ Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω Ω

5. ELECTROMAGNETIC WAVES AND WAVE OPTICS

ONE MARKS – BOOK BACK( VVI )

5.1 In an electromagnetic wave(a) power is equally transferred along the electric and magnetic fields(b) power is transmitted in a direction perpendicular to both the fields

(c) power is transmitted along electric field (d) power is transmitted along magnetic field5.2 Electromagnetic waves are(a) transverse (b) longitudinal(c) may be longitudinal or transverse (d) neither longitudinal nor transverse

5.3 Refractive index of glass is 1.5. Time taken for light to pass through a glass plate of thickness 10 cm is(a) 2 × 10 –8 s (b) 2 × 10 –10 s (c) 5 × 10 –8 s (d) 5 × 10 –10 s

5.4 In an electromagnetic wave the phase difference between electric field E

and magnetic field B

is(a) π/4 (b) π/2 (c) π (d) zero

5.5 Atomic spectrum should be(a) pure line spectrum (b) emission band spectrum(c) absorption line spectrum (d) absorption band spectrum.

5.6 When a drop of water is introduced between the glass plate and plano convex lens in Newton‟s rings system, the ringsystem(a) contracts (b) expands (c) remains same (d) first expands, then contracts

5.7 A beam of monochromatic light enters from vacuum into a medium of refractive index μ. The ratio of the wavelengths ofthe incident and refracted waves is(a) μ : 1 (b) 1 : μ (c) μ2 : 1 (d) 1 : μ2

5.8 If the wavelength of the light is reduced to one fourth, then the amount of scattering is(a) increased by 16 times (b) decreased by 16 times(c) increased by 256 times (d) decreased by 256 times

5.9 In Newton‟s ring experiment the radii of the mth and (m + 4)th dark rings are respectively √ 5 mm and √ 7 mm. What is thevalue of m?(a) 2 (b) 4 (c) 8 (d) 10

5.10 The path difference between two monochromatic light waves of wavelength 4000 Å is 2 X 10−7 m. The phase differencebetween them is(a) π (b) 2π (c) 3 π /2 (d) π/2

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5.11 In Young‟s experiment, the third bright band for wavelength of light 6000 Å coincides with the fourth bright band foranother source in the same arrangement. The wave length of the another source is(a) 4500 Å (b) 6000 Å (c) 5000 Å (d) 4000 Å

5.12 A light of wavelength 6000 Å is incident normally on a grating 0.005 m wide with 2500 lines. Then the maximum order is(a) 3 (b) 2 (c) 1 (d) 4

5.13 A diffraction pattern is obtained using a beam of red light. What happens if the red light is replaced by blue light?(a) bands disappear (b) no change

(c) diffraction pattern becomes narrower and crowded together(d) diffraction pattern becomes broader and farther apart5.14 The refractive index of the medium, for the polarising angle 60o is

(a) 1.732 (b) 1.414 (c) 1.5 (d) 1.468

PTA QUESTIONS ( IMPORTANT )

1. Angle between the electric component and the magnetic component of an electromagnetic wave is(a) 0 (b) /4 (c) /2 (d)

2. Phase difference between the electric field and the magnetic field of an electromagnetic wave is(a) 0 (b) /4 (c) /2 (d)

3. The velocity of electromagnetic wave in vacuum or free space is

(a) 100 (b) 00 (c) (d) 00 4. Existence of electromagnetic waves was confirmed experimentally by

(a) Maxwell (b) Henry (c) Hertz (d) Huygen5. In Hertz experimental arrangement, the two metal plates A and B are placed with a separation of

(a) 6m (b) 60 mm (c) 6 cm (d) 60 cm 6. Frequency of electromagnetic waves produced by Hertz arrangement was about

(a) 5x107Hz (b) 50x107 Hz (c) 8x1014 Hz (d) 4x1014 Hz7. Physical properties of the electromagnetic waves are determined by their

(a) wavelength (b) sources (c) method of excitation (d) all these8. Frequency band of radio waves used cellular phones is

(a) high (b) low (c) ultra high (d) very low

9. Radiation used to destroy bacteria and for sterilizing surgical instruments are(a) radio waves (b) X-rays (c) UV radiations (d) gamma rays

10. Radiation used in the detection of forged documents and finger prints in forensic lab is(a) IR rays (b) UV rays (c) gamma rays (d) X-rays

11. Wavelength of two sodium lines (D1 and D2) are(a) 8590Ao and 8596Ao (b) 5893Ao and 5890Ao (c) 5896Ao and 5890Ao (d) 6958Ao and 6950Ao

12. Spectrum produced by the incandescent solids at high temperature is(a) continuous emission spectrum (b) line spectrum(c) continuous absorption spectrum (d) line absorption spectrum

13. Spectrum produced by the electric filament lamp(a) depends on the temperature of the source (b) independent of temperature of the source(c) depends on characteristics of the source (d) depend on the method of excitation

14. Free excited atoms emit-------------- spectrum(a) continuous emission (b) line emission (c) band emission (d) line absorption

15. When the temperature of the solid is increased, the spectrum spread from(a) red to green (b) blue to green (c) red to blue (d) violet to red

16. Dark line appearing in the solar spectrum are called(a) Raman lines (b) Tyndall lines (c) Fraunhoffer lines (d) Rayleigh lines

17. Temperature of sun‟s outer layer is about (a) 14x106K (b)14x107K (c) 600K (d) 6000K

18. Lifetime of the substance exhibiting the phenomenon of fluorescence is(a) more than 10-5 s (b) equal to 10-5 s (c) less than 10-5 s (d)equal to 103 s

19. Delayed fluorescence is known as(a) luminescence b) bio-luminescence (c) phosphorescence (d) reflection20. Strength of scattering depends on

(a) wavelength of light (b) size of the particle (c) both (a) and (b) (d) velocity of light

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21. Absorption of light by the molecules, followed by its re-radiation in different directions is called(a) reflection (b) multiple reflection (c) scattering (d) dispersion

22. In Raman effect, lines of shorter wavelength are called(a) Stokes lines (b) anti stokes lines (c) Raman lines (d) Rayleigh lines

23. In Stokes lines, energy of scattered photon is(a) equal to energy of incident photon (b) lesser than the energy of incident photon (c) greater than the energy of the incident photon (d) zero

24. Raman shift is(a) independent of the frequency of incident light (b) characteristics of the substance (c) independent of the characteristic of the substance (d) both (a) and (b)

25. A linear source of light at infinite distance in an isotropic medium emits a _______ wavefront(a) spherical (b) cylindrical (c) circular (d) plane

26. If o is the frequency of incident radiation and s is the frequency of scattered radiation of given molecular sample, thenRaman shift or Raman frequency () is given by(a) = o - s (b) = s - o (c) = s + o (d) = 2(o - s)

27. If the path difference between two monochromatic wave is , the phase difference must be

(a) 2 (b)2 (c)

(d)

2

28. Colours in the thin film is due to

(a) dispersion of light (b) scattering of light (c) interference of light (d) reflection of light29. A ray of light traveling in a rarer medium, gets reflected at the surface of a denser medium. The automatic path changeproduced is(a) (b) 3 / 4 (c) / 2 (d) / 4

30. In Newton‟s ring experiment, the radius of the n th dark ring is proportional to(a) n (b) n2 (c) (d) 1

31. Bending of light waves around the edges of an obstacle is known as(a) reflection (b) diffraction (c) refraction (d) polarization

32. In case of Fraunhofer diffraction, the incident wavefront is(a) spherical (b) cylindrical (c) elliptical (d) plane

33. In Fresnel‟s diffraction, the shape of the incident wavefront is

(a) spherical (b) cylindrical (c) plane (d) (a) or(b)34. The point on the successive slits separated by a distance equal to grating element are called as(a) identical points (b) grating points (c) corresponding points (d)equal points

35. Transverse nature of electromagnetic waves was confirmed by the phenomenon of(a) interference (b) diffraction (c) polarization (d) reflection

36. In the propagation of light waves, the angle between the plane of vibration and plane of polarization is(a) 0° (b) 90 ° (c) 45 ° (d) 180 °

37. In case of partially polarised light, when the analyzer is rotated through 90 , the intensity of light beam varies from(a) maximum to zero (b) zero to maximum (c) maximum to minimum (d) remains same

38. The polarizing angle for glass is(a) 57.5 ° (b) 52.5 ° (c) 32.5 ° (d) 37.5°

39. In the arrangement of pile plates, the glass plates are inclined at an angle of ______with the axis of the tube(a) 57.5 ° (b) 52.5 ° (c) 32.5 ° (d) 37.5°

40. ________ is an example for uniaxial crystal(a) mica (b) topaz (c) selinite (d) quartz

41. Of the following optically active material is(a) sodium chloride (b) calcium chloride (c) sodium (d) chlorine

42. Instrument used to determine the optical rotation produced by the substance is________(a) interfero meter (b) Jamin‟s photometer (c) poloriscope (d) polarimeter

43. In Raman effect, Raman shift in frequency is always(a) positive (b) negative (c) negative for Stoke‟s lines and positive for antistoke‟s lines(d) positive for Stokes lines and negative for antistoke’s lines

44. The ratio of scattering powers of two wavelengths 400nm and 6000Ao is

(a) 81 : 16 (b) 16 : 81 (c) 81 : 64 (d) 64 : 81

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PUBLIC QUESTIONS ( VVI )

1) The existence of electromagnetic waves was confirmed experimentally bya) Hertz b) Maxwell c) Huygens d) Planck

2) When a ray of light is incident on a glass surface at polarizing angle of 57.5o, the angle between the incident ray and thereflected ray isa) 57.5o b) 32.5o c) 115o d) 90o

3) Unpolarised light passes through a tourmaline crystal. The emergent light is analysed by an analyzer. When the analyzeris rotated through 90o, the intensity of lighta) remains uniformly bright b) remains uniformly darkc) varies between maximum

+2 - physics em vvi 1mark qb by raja sheker.pdf

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