physics paper

CBSE Board Previous Year Question Papers 2007 for Class 11 Physics

Previous Paper – 2007

Class – XI

Subject - Physics

TIME: 3hr. MM: 70

General Instructions.

1. Questions from question no. 1-8 carry 1marks each, 9-18 carry 2 marks each, 19-27 carry 3 marks each and 28-30 carry 5 marks each.

2. There is no overall choice but one choice is given in 2 marks question, two choice in 3 marks question and all three choices in five marks question

3. You may use the following physical constant where ever necessary:Speed of light C = 3 x 108 ms-1

Gravitational constant G= 6.6 x 10-11 NM2 Kg-2

Gas constant R= 8.314 J Mol-1 k-1

Mass of electron = 9.110 x 10-31 Kg

Mechanical equivalent of heat = 4.185 J Cal-1

Standard atmospheric pressure = 1.013 x 105 Pa

Absolute zero 0k = - 273.150c

Acceleration due to gravity = 9.8 Ms-2

1. If a composite physical quantity in terms of moment of inertia I, force F, velocity V,work W and length L is defined as,Q = (I F V2 /WL3)

Find the dimension of Q and identify it.

2. Explain why a man who fall from a height on a cemented floor receive more injurythen when he fall from the same height on the heap of sand.

3. Is it possible to have a collision in which all the kinetic energy is lost? If so cite an example.

4. You are given two spheres of the same mass, size and appearance, but one of them is solid while the other hollow. If they are allowed to roll down an incline whichOne will reach the bottom first?

5. Can every oscillatory motion be treated as simple harmonic motion in the limit of small amplitude?

6. If the earth be at one half its present distance from the sun how many days will their be in a year?

7. A 25 cm long tube closed at one end is lowered with his open end down into a fresh water lake. If one- third of the tube is filled with water then what is the distance between the surface of lake and level of water in the tube.

8. Why zeroth law of thermodyamics is not called as IIIrd law though it was discovered after I and II law?

9. Define uniform velocity of an object moving along a straight line. What will be shape of velocity time and position time graphs of such a motion?

10. What do you mean by a projectile? A projectile is fired with velocity v making an angle Ө with the horizontal. Show that its path is parabolic.

11. Define the term momentum and impulse also derives the relation between them.

12. Define and explain moment of inertia of a rigid body about an axis of rotation. Hence define radius of gyration.

13. What do understand by gravitational field and gravitational field intensity? Show that acceleration due to gravity is a measure of the gravitational field of earth at a point.

OR

Define escape velocity. Derive an expression for escape velocity of an object from

the surface of a planet.

14. State newton’s law of cooling. Deduce the relationlog (Ө- Ө0) = - k t + c

15. In a refrigerator, heat from inside at 277K is transferred to a room at 300K. How many joule of heat will be delivered to the room for each joule of electrical energy

consumed ideally?

16. Give the essential features of the kinetic theory of gases. Show that the pressure exerted by a gas is equal to two-thirds the of the average kinetic energy per unit volume of the gas molecule.

17. State Newton’s formula for velocity of sound in gases. Discuss Laplace correction. What is the effect of density and pressure and temperature on velocity of sound in air? Explain.

18. What are centripetal acceleration and centripital force? Derive expression for them.

19. What is elastic collision? Calculate the velocities of the two bodies undergoing elastic collision in one dimension.

20. Show that the acceleration of free fall g at the surface of earth and the gravitational constant G are related by the expression

g = 4\3 Π p G R,

21. State the conditions, which are necessary for a satellite to appear stationary. Showhow an satellite orbiting round earth obey Kepler’s third law.

22. Find the maximum length of a steel wire that can hang without breaking.Given that breaking stress for steel = 7.9 x 1011 N M-2 and density of steel =7.9 x103 Kg M-3

OR

Define young’s modulus of elasticity, normal stress and longitudinal strain. Giveunits of each of them. Derive elastic potential energy of a wire when stretched.

23. The weight of a body in water is one third of its weight in air. What is the densityOf the material of the body.

OR

What is stokes law? Explain terminal velocity and mention its importance

24. Show that for a carnot engine, efficiency of the engine is >η = 1- T2/T1 (T2 > T1)Where T1 is the temperature of the source and T2 is the temperature of the sink.

25. If the orbital velocity of moon is increased by 42% than what will happen to itsposition? Explain.


SAMPLE PAPER - 2005Class - XISubject - Physics (Theory)Time: 3 hours Max. Marks 70

General Instructions1.All questions are compulsory. Symbols have their usual meaning.2.Q.No. 1 to 8 are of very short answer type questions, carrying 1 mark each.3.Q.No.9 to 18 are of short answer type questions, carrying 2 marks each.4.Q. No. 19 to 27 carry 3 marks each.5.Q. No. 28 to 30 carry 5 marks each.6.Use of calculator is not permitted. However you may use log table, if required.7.Draw neat labelled diagram wherever necessary to explain your answer.

1.What does speedometer of a car indicates?

2.Write down the dimensions of viscosity coefficient.

3.What is the effect on viscosity of gases when temperature is increased?

4.A light body and heavy body have equal momentum, which one have greater kinetic energy?

5.Why do we use ball –bearings?

6.State Newton’s universal law of gravitation and express it in vector form.

7. Calculate the moment of inertia of a uniform ring of mass 500 g and radius10 cm, about its diameter.

8. What would be the excess pressure inside a water bubble of radius 0.2 mm?Surface tension of water atC is 0.72 X N/m

9. How errors are combine in following mathematical operations of physical quantities?i) Subtraction ii) Product

10. Draw the Velocity – Time graph for following cases wheni) Object is moving in positive direction with accelerationii) An object is under free fall

11. Find the torque of a force 7i+3j-5k about the origin. The force acts on a particle

whose position vector is i-j +k.

12. Derive the necessary relation for safest velocity of an automobile on a banked road ofradius r and friction coefficient .

13. The escape velocity (v ) of a body depends upon the mass (m) of body, gravitationalacceleration (g) and radius(R) of the planet .Derive the relation for escape velocity dimensionally.

14. State and Prove Work- Energy Theorem.

15. Derive the necessary relation for orbital velocity of a satellite and prove thatusing it.

16. What do you mean by positive, negative and Zero work done .Give at least oneexample of each case.ORProve that mechanical energy remains conserved during motion when a body of massm is dropped from a height h.

17. Two masses 8 kg and 12 kg are connected at the two ends of an inextensible stringthat passes over a frictionless pulley. Find the acceleration of the masses and tensionin the string when masses are released.

18. Two bodies of masses (), moving with initial velocities, along a straight line in the same direction, suffer perfect head on collision. Find their velocities after collision.

19. State Hooke’s law. Explain Stress – Strain curve of a material when subjected underextended load.

20. State Parallelogram law of vector addition. Find the magnitude and direction of theresultant of two vectors A and B in terms of their magnitudes and angle betweenthem.


Previous Paper – 2008Class- XISubject - Physics

Q.1> When a man jumps out of a boat, the boat tends to move in the backward direction. Explain this phenomena on the basis of(a)Concept of center of mass(b)Newton’s third law(c)Conservation of momentum

Q.2> A particle of mass 5kg is kept at the point 2i + 3j + 7k. Another particle of mass 3kg is kept at the point having position vector 5i – 7j –k. Find the position vector of the CoM. If no external force is acting on the system, how would the position of CoM change?

Q.3> A particle “P” having mass 1kg is moving with a velocity of 3i + 7j m/s. Another particle “Q” of mass 2kg is moving with a velocity of 6j – k m/s. Find the velocity of CoM. How would the velocity of CoM change if no external force is acting on the system?

Q.4> Using the method of integration derive the moment of inertia for following mass distributions(a)Thin rod of mass M and length L rotating about an axis through the CoM(b)Thin rod of mass M and length L rotating about an axis passing through one of its ends(c)Circular ring of mass M and radius R(d)Circular disc of mass M and radius R

Q.5> Explain why earth and moon revolve around their common center of mass. Draw suitable figure

Q.6> What is center of gravity? How is it different from center of mass?

Q.7> A fan has a moment of inertia of 10kgm2. After being switched on, it attains a speed of 240rpm in10 seconds. What is the torque provided by the motor? What is the work done by the motor in bringing the fan to this speed?

Q.8> The radius of the wheels of a bike is 25cm. On acceleration, the bike can reach a speed of72kmph in just 6 seconds. What is the torque produced by the engine?

Q.9> A force F = 4i + 7j – 2k acts on a particle whose position vector is r = 6i – j + 3k.

The particle is free to rotate about an axis passing through the origin. Find the torque produced by the force.

Q.10> To maintain a fan at a constant speed of 10rad/sec the motor has to provide a torque of 100Nm. Explain why this torque is required for maintaining a constant speed. What is the power delivered by the motor?

Q.11> A torque of 10Nm acts on a ring of mass 2kg and radius 1m. Find the angle through which the ring will rotate in 5 seconds. What is the final angular velocity?(b) Using two different approaches, find the amount of work done by the applied torque.

Q.12> Define a couple. Two equal and opposite forces of 50N are acting at the opposite end of a rod of length 1m. What is the net torque and net force?

Q.13> The length of a boat is 10m and its mass is 100kg. A person of mass 50kg is standing at the left corner. As the person moves towards the right, the boat starts drifting towards the left. Explain why ??The person moves a total of 5m with respect to the boat. By how much would the boat drift?

Q.14> A solid sphere is rolling on the horizontal surface. What fraction of its total kinetic energy is associated with its rotational motion.

Q.15> A solid cylinder of mass M and radius R is kept on a rough inclined plane of inclination θ and is allowed to roll down. Find its acceleration and the force of friction acting on it. What is the minimum coefficient of friction required for pure rolling to take place?

Q.16> Draw a table showing the analogy b/w linear motion and rotational motion.

Q.17> Explain how the knowledge of conservation of angular momentum is useful to a diver.

Q.18> A body “P” having mass 5kg is kept at x = 2. Another body “Q” of mass 10ks is kept at x = 8. Due to their mutual force of gravitational attraction they start moving towards each other. Find the position at which they will collide.

Q.19> What is radius of gyration. Mention its units and dimension.

Q.20> A wheel of mass M is rotating with a constant angular velocity of ω. Two particles of mass m each are attached to its corner. How does this affect the angular velocity?

Q.21> The density of a rod varies as d = 10 – 5x. The length of the rod is 1m. Find its moment of inertia about an axis passing through one of the ends ( x = 0 )

Q.22> A boat is 20m wide and its mass is 500kg. A person of mass 100kg is standing at

the center. As the person moves towards the right, the boat starts drifting towards the left. The person continues moving towards the right till he reaches the end. Find(a)By how much would the boat drift?(b)What is the actual displacement of the person.

Q.23> Mention the units and dimension of the following quantities.(a)Torque(b)Moment of inertia(c)Angular momentum(d)Angular impulse(e)Rotational kinetic energy

Q.24> A radius of the wheels of a car is 20cm. The car is moving with a constant velocity of 10m/s. The maintain the rotation of the wheels, the engine has to deliver a torque of 125Nm. What is the power of the engine?

Q.25> A rod of length 5m is supported by two strings as shown inthe figure. It is made of a material of non-uniform density because 60o 30o of which the center of mass does not lie at the geometrical center.The rod is in a position of equilibrium, translational as well asrotational. This means that the net force as well as the net torqueacting on it are zero. Find the position of CoM(b) In which of the ropes is the tension greater?(c) The same rod is now suspended by two vertical strings. Find the tension in both the strings. The mass of the rod is 4kg


Previous Paper 2009Class - XISubject - Physics (Theory)Time: 3 hours Max. Marks 70General Instructions1. All questions are compulsory. Symbols have their usual meaning.2. Use of calculator is not permitted. However you may use log table, if required.3. Draw neat labelled diagram wherever necessary to explain your answer.4. Q.No. 1 to 8 are of very short answer type questions, carrying 1 mark each.5. Q.No.9 to 18 are of short answer type questions, carrying 2 marks each.6. Q. No. 19 to 27 carry 3 marks each. Q. No. 28 to 30 carry 5 marks each.

1. What is the ratio of A.B to A X B when angle between A and B is 600?

2. Write down the dimensions of universal gravitation constant .

3. What is the effect on viscosity of gases when temperature is increased?

4. A light body and heavy body have equal momentum , which one have greater Kinetic energy ?

5. Two absolute scales A and B have triple points of water defined to be 275 A and50 B. What is the relation between TA and TB .

6. State Newton’s universal law of gravitation and express it in vector form.

7. Calculate the moment of inertia of a uniform ring of mass 200 g and radius 20 cm, about one of its tangent which is perpendicular to the plane of ring.

8. What would be the excess pressure inside a mercury drop of radius 0.8 mm?Surface tension of mercury at 200 C is 465 X 10 3 N/m

9. A physical quantity P is related to four observables a,b,c and d as follows ; P = √abThe percentage errors in a,b,c and d are 2%, 4% ,3% and 2% respectively. What is the percentage error in the quantity P .

10. Draw the Velocity – Time graph for following cases when ( i) Object is moving with positive acceleration ( ii) An object is under free fall

11. Explain following with proper reason.(a) Why blood pressure in humans is greater at the feet than at brain.

(b) Water wets the glass surface while mercury does not.

12. Derive the necessary relation for safest velocity of an automobile on a bankedroad of radius r and friction coefficient .

13. Explain with reason Why:(a) A brass tumbler feels much colder than a wooden tray on a chilly day.(b) The earth without its atmosphere would be inhospitably cold.

14. State and Prove Work- Energy Theorem for variable force case.ORWhat do you mean by conservative and non conservative force. Give one example of each case.

15. Derive the necessary relation for orbital velocity of a satellite and prove that T2R 3 using it.

16. The Energy of a body executing SHM depends on the mass m, its frequency fand amplitude a. Derive the relation for energy using dimension methos.

17. State Hooke’s law. Explain Stress – Strain curve of a material when subjected under extended load.

18. A body of mass m 1 moving with velocity u 1 along a straight line collide with another body of mass m2 , perfect elastically, which is initially at rest. . Findtheir velocities after collision.

19. What do you mean by acceleration due to gravity? Derive the necessary relation for variation of g with depth.

20. State Parallelogram law of vector addition. Find the magnitude and direction of the resultant of two vectors A and B in terms of their magnitudes and angle between them.

21. Two masses 8 kg and 12 kg are connected at the two ends of an inextensible string that passes over a frictionless pulley. Find the acceleration of the masses and tension in the string when masses are released.

22. Define molar specific heat capacities at constant volume and pressure. Show that CP - CV= R. Where Symbols have their usual meaning.

23. State Stokes’ law and derive the expression for critical velocity in case of a small Spherical body falling through a viscous fluid like Glycerine.

24. State Pascal’s law. How it can be used in Hydraulic lift.

25. (a) Three bodies of identical radii ,a ring a solid sphere and a solid cylinder roll down the same inclined plane without slipping. They start from rest. Which of the bodies reaches the ground with maximum velocity ?(b) State the Parallel Axes theorem of moment of inertia.OR(a) A metal bar 70 cm long and 4 kg in mass supported on two knife edges placed10 cm from each end. A 6 kg load is suspended at 30 cm from one end. Find thereactions at the knife edges. Assume the bar to be of uniform cross section andhomogeneous.(b) State the theorem of perpendicular axes of moment of inertia.

26. Define Centre of mass. A body projected into space explodes. What will be thenature of path of its core?

27. If Earth were suddenly shrink to ½ of its present radius without change in mass,What is the effect on duration of day?

28. (a) What is angle of contact? When it is obtuse ? When it is acute?( b) Show that excess pressure inside a drop of radius r is Pi – Po = 2S /R .ORState and prove Bernoulli’s theorem. Explain any one application of it.

29. Answer any three from following.(a) Suggest some ways to minimize friction. (b) Explain why it is easier to pull a roller than to push it.(c) A constant force acting on a body of mass 3 kg changes its speed from 2 ms-1

to 3.5 ms-1in 25 s. The direction of the motion of the body remains unchanged. What is the magnitude and direction of the force. OR(a) Passengers are thrown forward from their seats when a speeding bus stopssuddenly. (b) A cricketer moves his hands backwards while holding a catch.(b) An aircraft executes a horizontal loop at a speed of 720 km/h with its wings banked at 150. What is the radius of the loop.

30. (a) Derive the equation v(b) A ball is thrown vertically upward with a velocity 20 m/s from the top of a multistory building. The height of the point from where the ball is thrown is 25 m from the ground, i) How high the ball rise? ii) With what velocity

strike the ground ?OR (a) A projectile is fired in air making an angle with horizontal. Show that(i) Its path is parabolic in nature. (ii) tan ɵ = 4H / R where H is maximum height attained and R is the range of projectile.(b) An aircraft executes a horizontal loop of radius 1.00 km with a steady speed of 900 km/h. Compare its centripetal acceleration with the acceleration due togravity


Sample Paper – 2010Class – XISubject – PhysicsTime : 1:30 hr MM : 60I.Answer the following questions: (1 Marks each)

a)What are the fundamental forces of physics?b)What do you mean by inertia?c)Calculate the angle of 1’ and 1’’.d)1 fermi = _____m 1Aº = _____m 1 astronomical unit = _____m 1 light year = _____m)What are strong and weak nuclear forces?f)What is the difference between distance and displacement?g)What do you mean by relative velocity?h)State for each of the following physical quantities , if it scalar or a vector:volume, mass, speed, acceleration, density, angular frequency, displacement, number of moles.i)What do you mean by instantaneous velocity?j)State Newton’s first law of motion.

II.Answer the following questions: ( 2 marks each)

a)What is parallax? How can we use the parallax method to find infinite distance?b)The moon is observed from tw diametrically opposite points A and B on the earth.The angle ᶿ subtended at the moon by the two directions of observation is 1º54’. Given the diameter of the earth to be about 1.276X10⁶m. Compute the distance of the moon from the earth.c)Derive a relation for the force acting on a particle of mass ‘m’moving with velocity ‘v’ in a circle of radius ‘r’.d)Write the dimensional equation of acceleration, momentum, force and Kinetic Energy.e)A cricket ball is thrownat a speed of 28m/sec.Calculate a) the maximum height b)the time taken by the ball to return to the same level c)the distance from the thrower to the point where the ball returns to the same level.

III.Answer the following questions: ( any five - 3 marks each)

a)A ball is thrown vertically upwards with a velocity of 20 m/sec from the top of a multistory building.The height of the point from where the ball is thrown is 25m from the ground. a) how high will the ball rise? b) How long will it be before the ball hits the ground?b)A man walks on a straight road from his home to the market 2.5 km away with a speed

of 5km/hr.Finding the market closed,he instantly turns and walks back home with a speed of 7.5 km/hr. What is the a) magnitude of average velocity and b) average speed of the man over the interval of time (i) 0 to 30 min , (ii) 0 to 50 min, (iii) 0 to 40 minc)A particle starts from the orogin at t=0sec with a velocity of 10j m/sec and moves in the x-y plane with a constant acceleration of (8i + 2j) m/sec².

(a) At what time is the x- coordinate of the particle 16m? What is the y-coordinate of the particle at that time?

(b)what is the speed of the particle at the time?

d)In a harbour,wind is blowing at the speed of 72 km/hr and the flag on the mast of the boat anchored in the harbour flutters along the N-E direction.If the boat starts moving at a speed of 51km/hr to the north,what is the direction of the flag on the mast of the boat?

e)State and derive newton’s second law of motion.

f)A constant force acting on a body of mass 3kg changes its speed from 2 m/sec to 3.5 m/sec in 25sec.The direction of the motion of the body remains unchanged.What is the magnitude and direction of the force?

IV.Answer the following questions: ( any five - 5 marks each)

a)(i) What is projectile motion? (ii) A hiker stands on the edge of a cliff 490m above the ground and throws a stone horizontally with an initial speed of 15m/sec.Neglecying air resistance find the time taken by the stone to reach the ground, and the speed with which it hits the ground.

b)(i) Find the magnitude and direction of the resultant of two vectors A and B in terms of their magnitude and angle ᶿ between them. (ii) Define law of sines and law of cosines.

c)(i)What do you mean by static friction? (ii) In the figure1.1 , A mass of 4 kg rests on a horizontal plane. The plane is gradually inclined until at an angle ᶿ= 15⁰ with the horizontal , the mass just begins to slide. What is the coefficient of static friction between the block and the surface?

d)A body of mass 0.40kg moving initially with a constant speed of 10m/sec to the north is subject to a constant force of 8 N directed towards the south for 30 sec. Take the instant the force is applied to be t=0, the position of the body at that time to be x=0, and predict its position at t= -5sec, 25 sec,100 sec.e) Derive kinematics equation for uniformly accelerated motion.

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