A LABORATORY MANUAL CUM OBSERVATION IN

PHYSICS FOR II P U (AS per the new syllabus)

PHYSICS PRACTICALS

IMPORTANT DISCOVERIES IN PHYSICS

1. Theory of relativity ,photoelectric effect –Albert Einstein

2. Law of gravitation, corpuscular theory of light –Issac Newton.

3. Raman effect – Sir C.V Raman.

4. Evolution of stars –S.Chandrashekar

5. Wave theory of light –Huygen.

6. Electromagnetic theory –Max well

7. Quantum theory of radiation –Max planck

8. Electron –J. J Thomson

9. Nucleus –Ruther ford

10.Neutron – James Chadwick

11.Radioactivity –Henry Becqueral

12.X- ray –Roentgen

13.Laser –Theodore Mainman

14.Superconductivity –Kamerlingh Onnes

15.Transistor –Bardeen ,Brattain & Shockley

16.Electric bulb –Thomas Alva Edison

17.Telephone –Graham Bell.

18.Refrigerator – Caree

19.Steam Engine – Thomas Newcomen

20.Electromagnet –William Sturgeon

21.Barometer – Toricelli

22.Cyclotron –Lawrence

23.Rocket –Robert Goddard

24.Discovery of expanding universe –Hubble.

25.Thermal Ionisation – M N Saha

26.Wireless telegraphy –Marconi

27.Colour Photography – Lippman

28.Holography –Gavor

29.Dynamo –Faraday

30.Logarithms – John Napier

PHYSICS PRACTICLS

List of Experiments:

1. To find ‘f’ by shift method and ‘n’ of a convex lens

2. To find the dispersive power of a prism using spectrometer

3. Air wedge –To determine thickness of paper by interference pattern

4. Grating –To determine the wavelength of the spectral lines by using a diffraction

grating

5. Polarimeter –To determine the specific rotation of sugar solution using Laurent’s

half –shade polarimeter

6. Ohm’s law –To verify Ohm’s law and the laws of combination of resistances

7. Meter bridge –To determine the resistivity of the material of a wire using a

meter bridge

8. Thermistor –To determine the temperature co-efficient of resistance of a

thermistor using a meter bridge

9. Potentiometer –To determine the internal resistance of a cell using

Potentiometer

10.Current sensitivity of a pointer galvanometer

11.Conversion of galvanometer into a voltmeter

12.Tangent galvanometer – To determine the reduction factor of TG and hence to

calculate horizontal component of earth’s magnetic field

13.Joule’s calorimeter – To determine the specific heat of a given liquid by

electrical method

14.Self inductance –To determine self inductance of a coil by direct method

15.To draw the forward bias characteristics of a semi conductor diode and hence to

determine Knee voltage and forward resistance.

16.Logic gates –To construct OR & AND gates using diodes and to verify their truth

table.

17.To determine the value of the given capacitor by drawing it’s charging and

discharging curves.

CONTENTS

EXPERIMENTS

1. Convex lens

2. Dispersive power of a prism

3. Air wedge

4. Diffraction grating

5. Polarimeter

6. Ohm’s Law

7. Meter bridge

8. Thermistor

9. Potentiometer

10.Current sensitivity of pointer galvanometer

11.Conversion of galvanometer into a voltmeter

12.Tangent galvanometer

13.Joule’s calorimeter

14.Self inductance

15.Semiconductor diode

16.Logic gates

17.Charging and discharging of capacitor

18.Log table

Scheme of Practical examination

The practical examination will be for duration of two hours .The maximum marks

allotted are twenty.

The scheme for allotment of marks is as follows

1. Relevant formula for the experiment (if there are two formulae 1 mark each)

2marks

2. For electrical experiments circuit diagram and for other experiments

of experimental set up. 2 marks

3. Brief procedure of the experiment

3Marks

4. Tabular column of the experiment 1

marks

5. Observation and entering the reading in tabular column

3 marks

6. Substitution and calculation using log tables

3 marks

7. Result with unit and accuracy

2 marks

8. Practical Record 4

marks

Total 20

Marks

CONVEX LENS

EXPT NO:1 Date:

Aim : To determine the focal length and refractive index of the material of a convex lens

Apparatus : Convex lens, lens holder, object screen, image screen, meter scale, etc

Formula : 1) focal length

Where, D= distance between the object and image screen

S = distance between the positions and of the lens

2) Radius of curvature

d = distance of the lens from the object.

3) Refractive index

and are the radii of curvature of the lens.

Diagram

f Rays from distant object

D>4f

S

1S 2S

IO

Procedure: I. Shift method: To find focal length of the lens.

1. Approximate focal length is determined by distance object method

2. Image screen is placed at a large distance D from the object (D>4f)

3. A lens is introduced between the object and image screen

4. The position of the lens is adjusted to get an enlarged image on the screen and the position

is marked

5. The lens is moved towards the screen to get a diminished image on the screen and the

position is marked

6. The distance S between the positions and is measured.

7. The focal length is calculated using the above formula

8. The experiment is repeated for the different values of D and the mean value of f is

calculated.

TABULAR COLUMN:

Trail

no

Distance

between object

and image

screen D(cm)

Distance between

and . S (cm)

1

2

3

Mean f = cm

II. Boy’s method: To find the radii of curvature

1. The lens is placed in front of the object.

2. The position of the lens is adjusted to get a sharp image of the object on the side of the

object

3. Distance between the lens and object screen is measured

4. Radius of curvature is calculated.

5. is measured by reversing the lens and the radius of curvature is calculated

6. The refractive index of the lens is calculated using the formula

Diagram

I surface = cm II surface = cm

1x

I

O

2x

I

O

Radius of curvature, cm cm

Substitution and Calculation:

Result:

1. The focal length of the convex lens = cm

2. Refractive index of the material of the lens =

DISPERSIVE POWER OF A PRISM

EXPT NO: 2 DATE:

Aim: To determine the dispersive power of a prism using a spectrometer Apparatus: Spectrometer, prism, mercury vapour lamp, spirit level, reading lens.

Formula: 1) Refractive index of the prism

A = angle of the prism.D = angle of minimum deviation

2) Dispersive power of a prism

= refractive index of the prism for blue.

=Refractive index of the prism for green

Where and are refractive indices of the material of the prism

Diagram:

1R

2R

Collimator

Prism Table

Telescope

A

B C

Prism Table

Telescop

e

0R

R

Collimator

Initial adjustment1. The telescope is turned towards a white wall and the eye piece is moved until the cross wires are

clearly seen.2. The telescope is turned towards a distant object .Rack and pinion screw of the telescope is adjusted

until a clear image of the distant object is seen.3. The collimator is placed in line with the given source. The telescope is placed in line with the

collimator. The rack and pinion screw of the collimator is adjusted until the image of the slit becomes sharp and the slit is made narrow.

4. Prism table is made horizontal by using spirit level and adjusting the leveling screw.

Procedure:I. To find the angle of prism (A)

1) The least count of the spectrometer is calculated 2) Prism is placed on the prism table.3) Telescope is turned towards one face of the prism to view the reflecting image of the slit.4) The image of the slit is made to coincide with the intersection of the cross –Wire MSR & CVD are noted

and the total reading is calculated.

5) found by turning towards the second face

6) Angle of prism is calculated

II. To determine the angle of minimum deviation (D)1. The prism is place on the prism table such that light from collimator on one of its refracting faces2. Telescope is turned towards the base of the prism to view the spectrum.3. Looking through the telescope at a particular spectral line the prism table is rotated such that the

line moves towards the collimator axis4. The prism table is fixed at the position where the spectral line just turns back. Now the prism is in

minimum deviation position.5. The telescope is adjusted in such away that vertical cross wire coincides with green colour. The

reading R is noted .6. The same procedure is repeated for blue colour and reading R is noted.7. Prism is removed and the telescope is aligned along the collimator axis.8. The direct reading Ro is noted9. Angle of minimum deviation for green ( ) and blue ( ) colors calculated.10. Dispersive power of the material of the prism is calculated using the formula.

Observation: To find the least count of spectrometer.Value of IMSD = S = degreeTotal no of the VSD = N =

Least count = = degree.

Tabular columnI. To find angle of prism (A)

MSR(degree)

CVD degree

MSR(Degree)

CVD

degree

degr

ee

II. To find angle of minimum deviation (D)

Direct reading degree

Colour MSR(degree)

CVD TR(R)Degree

Green Dg = ng=Blue Db = nb =

Substitution and calculation:

Result: Dispersive power of the material of the prism =

AIR WEDGEEXPT NO: 3 Date:

Aim : To determine the thickness of paper by interference pattern.Apparatus: Plane glass plates, traveling microscope, sodium vapour lamp, etc.

Formula : Thickness of the paper is given by

Where : = wave length of monochromatic light = 5893 L = length of the air wedge

fringe width

Diagram

Procedure:1. The least count of the traveling microscope is calculated.2. A thin paper is fixed at one end of the horizontal glass plate and the other glass plate is placed over

it to form an air wedge.

Microscope

Glass Plate

Paper

L

3. Light form the source falls on the wedge normally and the traveling microscope is adjusted to get an interference pattern consist of alternate dark and bright fringes and note down the reading of the microscope.

4. The vertical cross wire is made to coincide with central dark fringe and note down the reading of the microscope.

5. Experiment is repeated for successive dark fringe and note down the microscope reading.

6. The fringe width is calculated by the method of differences.7. The length L of the air wedge is measured.8. The thickness of the paper (t) is calculated using the above formula.

Observation:To find least count of traveling microscope.Value of I MSD = S = cmTotal no of VSD = N=

LC = cm

TABULAR COLUMN:Fringe no

TM reading Fringe no

TM reading Width of 25 fringes

cm

MSR cm

CVD

cm

MSR cm

CVD

cm

n n+ 25n+5 n+ 30n+10 n+35n +15

n +40

n+ 20

n +45

Mean fringe width. =

Length of air wedge L =

Substitution and calculation:

Result:The thickness of the paper is found to be = m.

DIFFRACTION GRATING

EXPT NO 4 Date:

Aim: To determine the wave length of the spectral lines by using diffraction grating.Apparatus: Diffraction grating, mercury vapour lamp, spectrometer, spirit level, etc.

Formula: Wave length of the spectral line is given by

Where C= Grating constant.D = Angle of minimum deviation.n = Order of the spectrum.

Diagram

Procedure:1. Least count of the spectrometer is calculated.2. Initial adjustments of the spectrometer are made

D

R

Collimator

Diffraction Grating

Prism Table

Telescope

0R

3. The grating is placed on the prism table such that the slit is parallel to the ruling of grating and the telescope is moved to one side to view the First order spectrum (n =1 ).

4. The grating is adjusted for the minimum deviation position.5. The telescope is adjusted to one of the spectral line and the reading R is noted.6. The procedure is repeated for other spectral lines.7. The grating is removed. The telescope is brought in line with collimator such that cross wire

coincides with the slit. Direct reading is noted.

8. Minimum deviation is found for each colour using .

9. By assuming , the grating constant C is calculated.

10. The wave length of different spectral lines is calculated using the above formula.

Observation: To find least count of spectrometer.Value of 1 MSD = S = degreeTotal no of VSD = N=

= degree

Wave length of green light

Order of spectrum, n =Direct reading Ro =

TABULAR COLUMN_____degree

Colors MSR(degree)

R (degree) degree

YellowGreenBlueViolet

Substitution & Calculation:

Result:1. Wave length of violet =

2. Wave length of blue =

3. Wave length of green =

4. Wave length of yellow =

POLARIMETEREXPT No:5 DATE:

Aim : To determine the specific rotation of sugar using Laurent’s half –shade polarimeter.Apparatus: Polarimeter, sodium vapour lamp, sugar, beaker, distilled water, filter papers, physical balance, etc

Formula : Specific rotation rad

Where, = Angle of rotation.C = concentration of sugar solution.L = Length of the polarimeter tube.

Diagram

Procedure:1. The polarimeter tube is filled with distilled water and placed in its position.2. The polarizer is illuminated with monochromatic light.

3. The analyzer A is rotated until both the halves of field of view appears equally bright. The reading

is calculated using the formula .

4. The water in the tube is replaced by sugar solution of known concentration (C).5. Again analyzer A is rotated until both the halves of field of view appears equally bright. The reading

R is noted.

6. The difference between R and gives angle of rotation

7. The value of is calculated.

8. The experiment is repeated for different concentrations (c) and the mean value of is found

9. The length (L) of the polarimeter tube is measured.10. The specific rotation of sugar solution is calculated

Polariser Half shade

Device

Sugar Solution

Analyser

Eye Piece

Source

polarimeter

Observation: To find least count of polarimeter Value of IMSD = S= degree

Total number of VSD =N =

LC = degree

Length of the polarimeter tube L =

Reading for distilled water = degree

Tabular column:Trial No

Concentration C Kg

R degree

Degree

123

Mean =

Result:

Specific rotation of sugar solution =

OHM’S LAWEXPT NO:6 DATE:

AIM: To verify Ohm’s law and the laws of combination of resistances.Apparatus: Battery, plug key, resistance coils, ammeter, voltmeter, rheostatFormula :

1. Resistance of the given coil

Where, V=potential difference across the coil.I = Current through it

2. For series combination

Where, and are the individual resistances.

3. For parallel combination

Circuit

Procedure:a) Verification of Ohm’s law.

1) Circuit connections are made as shown in figure.2) The key is closed and the rheostat is adjusted for small current3) Ammeter reading I and corresponding voltmeter reading V are noted.4) The ratio V/I is calculated5) Experiment is repeated for different values of current by adjusting the rheostat and

corresponding voltmeter reading are tabulated, the ratio V/I is calculated in each case.6) The ratio V/I is found to be constant in each trial, this verifies Ohm’s law.

Tabular column

A

V+ -

Rh

-+ Pk

Ba

To find

Mean =

To find

Trial no I(A) V(volts)

123

Mean =

b) Law of series combination.1) Circuit connections are made as shown in figure.2) The key is closed and the rheostat is adjusted for small current.3) Ammeter reading I and the corresponding voltmeter reading V are noted.

4) The effective resistance is calculated from V/I

5) Experiment is repeated for different values of current by varying the rheostat

6) is calculated.

7) It is found that which verifies the law of series combination.

Circuit

= =

Trial no

I (A) V (volts)

Mean

123

Result: In series

c) Law of parallel combination.1) Circuit connection is made as shown in the figure.2) The key is closed and the rheostat is adjusted for small current .3) Ammeter reading I and the corresponding voltmeter reading V are noted

4) is calculated .

5) Experiment is repeated for different values of current by varying the rheostat.

6) is calculated .

Trial no I(A) V(volts)

123

A

V+ -

Rh

-+ Pk

Ba

7) It is found that which verifies the law of parallel combination.

Results:

METRE BRIDGEEXPT NO: 7 DATE:

Aim: To determine the resistivity of the material of a wire using a meter bridge.

Apparatus: Meter Bridge, sliding contact, Galvano meter, wire, screw gauge, resistance box, etc.

Formula: 1) Resistance of the given wire

Where S = standard resistanceBalancing length

2) Resistively of given Wire

d = diameter of wire L = Length of the wire

Diagram

Procedure:1. Electrical connections are made as shown in figure.2. A suitable resistance S is unplugged from the resistance box and key is closed 3. The position of the sliding contact on the wire is adjusted for zero deflection in the galvanometer.4. The balancing length (AD) is measured and the resistance R is calculated by using the formula.

Trial no

I (A) V (volts)

Mean

123

A

V+ -

Rh

-+ Pk

Ba

1R

2R

( )Ba PK

lD

G

R

CA

X

5. Experiment is repeated for different values of S and in each case R is calculated.6. Length of wire (L) is measured 7. Diameter of the wire (d) is determined using screw gauge.8. Resistivity of the given wire is calculated.

Tabular Column:

To find unknown resistance(R)Trial no

123

Mean R=

Observation:

To find the diameter of the wire (d)

Pitch =

LC

ZE= division

Trail no PSR mm

HSR TR=PSR+(HSR-ZE) x LC mm

123

Mean d = mm= L =

Substitution & Calculation

Result: Resistivity of the given wire is found to be =

THERMISTOREXPT NO:8 DATE:

Aim: To determine the temperature co-efficient of resistance of a thermistor using a meter bridge.Apparatus: Meter Bridge, galvanometer, battery, resistance box, thermistor, beaker, thermometer etc.

Formula: 1) Resistance of the thermistor

Where S =standard resistance box.balancing length.

2) Temperature co-efficient of resistance of a thermistor is

Where and are the resistances of the given thermistor at temperatures and

respectively.

Diagram

Procedure:1. Electrical connections are made as shown in figure2. Thermistor is immersed in hot water.3. A suitable resistance S is unplugged from the resistance box and key is closed.4. Sliding contact is moved along the bridge wire until the galvanometer shows zero deflection. The

balancing length is measured and the corresponding temperature of hot water is measured. Resistance R of the thermistor at that temperature is calculated.

5. Experiment is repeated for every fall in temperature and the corresponding balancing lengths are noted.

6. Temperature co-efficient of resistance of a thermistor between any temperatures is calculated.

Tabular Column:

R

A

B

p

SD

G

Q

C

( )Ba

PK

Trial no

1 752 703 654 60

Calculation:

Result:The temperature co-efficient resistance of given thermistor = /K

POTENTIOMETEREXPT NO: 9 DATE:

Aim: To determine the internal resistance of a cell using a potentiometer.

Apparatus : Potentiometer, storage cell, plug keys, rheostat, resistance box , sliding contact, leclanche cell.

Formula:

Where r= Internal resistance of cell.R= Resistance unplugged from the resistance box

balance length when cell is in the open circuit

balancing length when cell is in the closed circuit.

Circuit

Procedure:1. Electrical connections are made as shown in the figure (care is taken that positive terminal of

storage battery and positive terminal of experimental cell are connected to the same end of the potentiometer wire)

2. The key is closed in the primary circuit and is kept open.

3. The jockey is adjusted for null deflection in the galvanometer. The balancing length is measured.

4. A suitable resistance r is calculated using the above formula.5. Internal resistance r is calculated using the above formula 6. Experiment is repeated for the mean value of internal resistance r is calculated.

Observation:

Ba

A B

E

R

G2l

2K

)

Balancing length = m

Tabular column:Trail no

R

123

Mean r =

Result:Internal resistance of the given cell is found to be =

CURRENT SENSITIVITY OF A POINTER GALVANOMETER

EXPT :10 DATE:

Aim: To determine the current sensitivity of a given pointer galvanometer Apparatus: Pointer galvanometer, fractional resistance box, two resistance boxes (0- 500 ), battery, key etc.

Formula:

Where, = current sensitivity E = emf of a cellG = galvanometer resistance

= deflection of galvanometerR = resistance unplugged from fractional resistance box

Circuit

Procedure:1. Circuit connections are made as shown in figure.2. Keeping X = 0, suitable resistance are unplugged from the boxes R & r

G

Pk

Ba

B

CD

Ar R

X

3. The key is close so that deflection in galvanometer is even number. The value of R,r and are noted.

4. The resistance X is adjusted until the deflection in galvanometer becomes the resistance unplugged in X is noted. It gives the value of G i.e (X=G)

5. Experiment is repeated for different values of R and r.6. The emf of a cell is measured using a voltmeter.7. is calculated in each trial and mean value is calculated.

Tabular Column:Trail No

R division

123 Mean A/div

Substitution & Calculation

Result:

Current sensitivity of the given pointer galvanometer = A/div

CONVERSION OF GALVANOMETER INTO VOLTMETER

EXPT NO:11 DATE:

Aim: To convert given galvanometer into a voltmeter of range (0-3V) volts.Apparatus: Galvanometer, standard voltmeter, resistance box, battery, rheostat, etc.

Formula: 1. Current for full scale deflection,

Where, = current sensitivity of a galvanometer scale.N = Total no of division on the galvanometer scale.

2. High resistance,

Where, V = Maximum pd to be measured G = Galvanometer resistance.

Circuit

Procedure:1. The galvanometer resistance G and the current for full scale deflection Ig are noted . High

resistance that required in series with galvanometer is calculated using the formula.2. Circuit connections are made as shown in the figure

)

G

R

V+ -

Converted voltmeter

Rh

( Ba

K

3. Rheostat is adjusted as to get suitable readings Vs in the standard voltmeter.4. The corresponding galvanometer deflection is noted. The reading of converted voltmeter is

calculated using Vc = (V/N)5. The error (Vs ~ Vc) volt is calculated.6. The experiment is repeated for different values of Vs.

Observation:1. Galvanometer resistance G =2. Current sensitivity = A/div3. Total no of division on the galvanometer scale (N) =4. Voltmeter range (V) = Volts.

Calculation of R.

Tabular Column:Trial No

Standard voltmeter reading Vs (volt)

Deflection division

Vs =(V/N) volt

Error (Vs ~Vc ) volts

123

Result:A galvanometer is converted into a voltmeter by connecting high

Resistance R = in series with given galvanometer.

TANGENT GALVANOMETER

EXPT NO: 12 DATE:

Aim: To determine the reduction factor of TG and hence to calculate the horizontal component of earth’s magnetic field .

Apparatus: TG, battery eliminator, rheostat, ammeter, commutator …..Formula:

1. Reduction factor

Where, I = current through TG.= mean deflection in the TG.

2. Horizontal component of earth’s magnetic field

Where permeability of free space n = number of the turns usedK = reduction factor.r = radius of the coil.

Circuit

Procedure:1. The TG is set into the magnetic meridian by making the following initial adjustment.

( Ba

)

A

+

Rh

Pk

-

)Commutator T

G

a) The base of the TG is made horizontal using spirit level b) The compass box is rotated until the line is parallel to the plane of the coil.c) The coil as a whole is rotated until the pointer reads 2. Electrical connections are made as shown in figure.3. By using the rheostat the current in the circuit is adjusted so that the deflections in the TG lies

between and4. The readings and are noted.5. The current through TG is reversed by using the commutator and the readings and are

noted.6. The mean value of is calculated . The ammeter reading I is noted.7. Experiment is repeated for different values of current and the reduction factor K is calculated

in each case.8. The horizontal component of earth’s magnetic field is calculated using the formula.

Observation:1. Circumference of the coil C = cm

2. Radius of the coil, r =

3. Number of turns used n =

Tabular column:Trial No

IA TG deflectionMean

123

Substitution & Calculation

Result : 1. Reduction factor of TG is found to be K = A2. Horizontal component of earth’s magnetic field = T

JOULE’S CALORIMETEREXPT NO:13 DATE:

Aim: To determine the specific heat of a given liquid by electrical method.Apparatus: Joule’s calorimeter, ammeter, voltmeter, thermometer, battery, rheostat, stop clock, key etc

Formula: Specific heat of liquid

Where, mass of calorimeter +stirrer =mass of calorimeter+ stirrer+ liquid

mass of liquidV = voltmeter readingI = ammeter readingt = time for which current is passed

= initial temperature of the liquid = final temperature of the liquid

Sc = specific heat of the material of the calorimeter

Diagram

)(

)(

)()( )

(

)(

)(

)(

)(

)()() (

( )Rh

Ba

Pk

V+ -

+ -

Procedure:1. Electrical connections are as shown in figure.2. Mass of empty calorimeter with stirrer is determined.

3. It is filled with 2/3rd of given liquid again weighed .

4. Initial temperature of liquid is noted.5. Key is closed and simultaneously stop clock is started.6. Ammeter reading (I) and voltmeter reading (V) are noted.7. Pass the current till the temperature of liquid raised by or 8. The circuit is broken by removing the key and the stop clock is stopped. Note down the time

taken.9. The liquid is stirred and final temperature is noted10. The specific heat is calculated using the formula.

Observation:1. Mass of empty calorimeter + stirrer, = Kg2. Mass of calorimeter + stirrer, = Kg

3. Mass of liquid Kg4. Specific heat of calorimeter, Sc =385 .5. Initial temperature of liquid +273= k6. Final temperature of liquid +273= k7. Time for which current is passed, t = sec8. Ammeter reading, I= A9. Voltmeter reading, V = V

Result:Specific heat of liquid =

SELF INDUCTANCEEXPT NO:14 DATE:

Aim: To determine self inductance of a coil by direct method.

Apparatus : AC/DC power supply, AC/DC ammeter, AC/DC voltmeter, coil, rheostat, etc.Formula:

Henry

Where, L= self inductance of a coil.Z= impedance of a coilR = resistance of a coil.

f = frequency of AC used.Circuits

Procedure:

I. DC part1. Electrical connections are made as shown in the figure using DC source and meters.2. Key is closed and the rheostat is adjusted for small current.3. Ammeter reading (I) and the corresponding voltmeter reading (V) are noted.4. The ratio V/I=R is calculated.5. Experiment is repeated for different values of current by varying the rheostat.6. R is calculated in each case and the mean value of R is calculated.

A

V+ -

Rh

+

-

kB

a

L

~

V

~`~V~

+ -

Rh

+

-

k

AC Source

LA~~

II. Ac part1. Electrical connections are made as shown in the figure using AC source and meters.2. Key is closed and the rheostat is adjusted for small current.3. Ammeter reading (I) and the corresponding voltmeter reading (V) are noted.4. The ratio V/I =Z is calculated.5. Experiment is repeated for different values of current by varying the rheostat.6. Z is calculated in each case and the mean value of Z is calculated.7. The self inductance of the coil is calculated using the formula.

Tabular column:

Trail no

DC part AC partI (A) V(v) I (A) V (v)

12345

Mean R = Mean Z =

Substitution & calculation:

Result: Self inductance of a given coil = Henry.

SEMICONDUCTOR DIODE

EXPT NO :15 DATE:

Aim: To draw the forward bias characteristics of a semiconductor diode and to determine knee voltage and forward resistance.Apparatus: Semiconductor diode, milliammeter, voltmeter, battery, rheostat.

Formula:

Diagram

Procedure:1. Electrical connections are made as shown in the figure.2. Voltmeter reading is increased gradually from zero in small steps by varying the rheostat. 3. Voltmeter readings (V) and corresponding ammeter readings (I) are tabulated.

I (m A)

A

BC

V (volt)

ABslope

BC

kV

mA+ -

Rh

V

Ba

PK

+ -

+ -

4. Graph of I versus V is plotted.5. The straight line portion of the curve is extrapolated to cut the voltage axis ,this gives knee

voltage .6. Slope of the straight line part of the curve is found. The reciprocal of the slope gives the

forward bias resistance of the diode.

Tabular column:V volt 0 0.1 0.2 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7I mA

Result: 1. Knee voltage = Volt.2. Forward bias resistance

CHARGING AND DISCHARGING OF CAPACITOR

EXPT NO: 17 DATE:

AIM: To determine the value of the given capacitor by drawing it’s charging and discharging curves.Apparatus: Capacitor, Voltmeter, Resistor, Battery, Stop clock, key etc.Formula:

Where, C=capacitance of a capacitor.=Average time

R = Resistance

Circuit:

Procedure:Charging of capacitor

1. Circuit connections are made as shown in the figure.2. Key is closed and simultaneously stop clock is started.3. The readings of the voltmeter at t = 0 second and after every 30 second are noted until it

reaches a maximum steady value4. Plot a graph of V versus t.

( ( )1K 2K

R

C

DCSource

V

5. From the graph, time corresponding to the voltage value of and

are found.6. From the know value of R, Capacitance of the capacitor is calculated using the formula.

I Charging: Times S

0 30 60 90 120 150 180 210

V volt

Discharging of capacitor 1. Key is closed and simultaneously stop clock is started.2. The reading of the voltmeter at t =0 seconds and after every 30second are noted until it reaches

a steady minimum value t.3. Plot a graph of V versus t.

4. From the graph, time corresponding to the voltage value of and are found

5. From the know value of R, Capacitance of the capacitor is calculated using the formula

II Discharging:Times S

0 30 60 90 120 150 180 210

V volt

Graph

a) Charging b) Discharging

Result:Capacitance of the given capacitor is found to be

1. During charging C =2. During discharging C=

Time

0V

00 2

VV

00 4

VV

O

V

Time

0V

0

2

V

0

4

V

O

2t1t

V

Logic GatesEXPT No: 16 Date

Aim: To construct OR and AND gates using diodes and verify their truth table

Apparatus : Diodes, resistors, 5 V DC power supply, Voltmeter etc.

Formula:1) For OR gate Y = A+B2) For AND gate Y = A.B

Where, Y=output state, A and B are the input state.

OR gate :circuit diagram:

Procedure:1. Construct OR gate circuit as shown in the figure2. Connect A to Zero (-ve terminal) of the battery and record the out put state.3. Connect A to Zero (-ve terminal) and B to l ( +ve terminal ) of the battery and record the out

put state4. Connect A to l and B to zero of the battery and record the output state5. Connect A to I and B to zero of the battery and record out put state6. Thus truth table of OR gate is verified

1D

2D

A

B

Y=A+B

R=470

AB

y =A+B

Truth table:A B Y = A +B Out put voltage0 0 0 Low0 1 1 High1 0 1 High1 1 1 High

AND gate :circuit diagram:

Procedure:

1. Construct AND gate circuit as shown in the figure2. Connect A and B to Zero (- ve terminal ) of the battery and record the output state3. Connect A to Zero ( - ve terminal ) and B (+ ve terminal ) of the battery and record the out put

state4. Connect A to l and B to zero of the battery and record the output state 5. Connect A and B to l of the battery and record the out put state6. Thus truth table of AND gate is verified

Truth table:

A B Y = A. B Out put voltage0 0 0 Low0 1 0 Low1 0 0 Low1 1 1 High

AB

y =A.B

1D

2D

A

B

Y=A.B

R=470

5V

Note: Out put voltage > 3.5v is taken as logic state l and less then 0.8v is taken as logic state ‘0’

Result:

OR and AND gates are constructed and their truth tables are verified.