Class 11- Physics

8/11/2019 Class 11- Physics

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QUESTION BANK

CLASS:11

SUBJECT:PHYSICS

Unit:1

PHYSICAL WORLD AND MEASUREMENT

Weightage-3

Very Short Answer Questions ( 1Mark Each)

1. Name the fundamental physical quantity whose SI unit has not changed since the inspection of

international system of units.

2. Write the dimensional formulae of (i) power (ii) surface tension.

3. Can a quantity have units but still be dimensionless?

4. Can a quantity have dimensions but still have no units?

5. Write 2 eg of non-dimensional variables.

6. Give the number of significant figures in (i) 0.270m (ii) 0.0027kg (iii) 27.00 (iv) 0 27x10-5

.

7. What type of waves are used in (i) RADAR (ii) SONAR?

8. What is the dimension of rate of flow?

9. Convert an acceleration of 10m/s2in cgs system.

10. Give approximate ratio of 1 AU and 1 light year.

11.Define accuracy.

12. What is precision in a measurement?

13.Which of the following is most accurate?(i) 4.00 cm (ii) 0.004 mm (iii0 40.00 cm.

14.What is the percentage error in volume of a sphere, when error in the measurement of its

radius is 2%?


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15.If the unit of force is 100N, unit of length is 10m and unit of time is 100s, what is the unit of

mass in this system of units?

Short Answer Questions ( 2 Marks each)

1. What is Physics? Discuss its relation with technology.

2. Name the 4 types of forces in nature.

3. State Avogadros hypothesis. Use it to estimate the size of an atom.

4. Discuss some methods to measure the distance of a near by heavenly object.

5. Define the error in a measurement and discuss its various types.

6. Show that the maximum fractional error in the product of two quantities is equal to the sum of

the fractional errors in the individual quantities.

7. What is meant by dimensional formula?

8. Give 2 uses of dimensional analysis.

9. Give some limitations of dimensional analysis.

10. The length of a rod was found to be 2.48m, 2.47m, 2.46m and 2.45m. Find (i) absolute errors

(ii) mean absolute error (iii) relative error (iv) percentage error.

11. Deduce the dimension formulae for gravitational constant, youngs modulus, Planck

constant.

12. The time period of a simple pendulum depends on the length of the pendulum and the

acceleration due to gravity. Obtain the expression for the time period dimensionally.

13. The velocity of the water waves depends on the wavelength density of the water and the

acceleration of the water due to gravity. Deduce by the method of dimensions the relationshipbetween these quantities.

14. A large star oscillates and the time period depends on the radius of the star, the density of the

fluid and the gravitational constant G. Obtain the expression for the time period dimensionally.

15. Check the correctness of the relation

1. =h/mv

2. T=2l/g


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3. F=mv/r


1. A substance weighing 5.74 g occupies a volume of 1.2 cm3. Calculate its density with due

regards to significant figures.

2. Discuss some indirect methods to measure distance

3. Explain the parallax method to measure the distance of moon from the earth.

4. Give a method to measure the diameter of the moon.

5. Discuss a method to measure the size of an atom.

6 Define some units for large and small lengths

7. Calculate the angle of (i) 1 (ii)1 (iii) 1 in radians.

8. Classify the physical quantities on the basis of dimensions. Are all constants dimensionless?

Comment.

9. The frequency of an oscillating drop may depend on the radius, density and the surface tension

of the liquid Deduce the formula dimensionally.

10. Discuss how errors propagate in sum, difference, product and division of quantities.

Unit:2

KINEMATICS

Weightage-10


1. Define a point object.

2. In which case the average speed equals average velocity?

3. What does the speedometer measure?

4. What do you get from area under v-t graph?

5. What will be the nature of x-t graph for a uniform motion?


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5. Can a body have a constant velocity and have a varying speed?

6. Can x-t graph be a straight line parallel to position axis?

7. Draw x-t graph for two objects having zero relative velocity.

8. Can three vectors lying in a plane give zero resultant?

9. Can the resultant of two vectors of different magnitudes be zero?

10. Even when rain is falling vertically downwards, the front screen of a moving car gets wet. On

the other hand, the back screen remains dry. Why?

11. A football is thrown in a parabolic path. Is there any point at which the acceleration isperpendicular to the velocity?

12. At which point of the projectile path, the speed is minimum?

13. A body is projected so that it has maximum range R. What is maximum height reached

during the flight?

14. Give some examples of motion in two dimensions.

15. Is it possible to have 2-D motion with acceleration in only 1-D?


1.Obtain the three equations of motion graphically.

2.Define relative velocity. Draw the x-t graph for the following situations

(i) vA >vB (ii) vA >vB .

3.Show that the flight of a bird is an example of composition of vectors.

4.State parallelogram law of vector addition and obtain the expression for the resultant.

5. Define uniform circular motion. Is it an accelerated motion?

6.What do you mean by (i) projectile motion (ii) range (iii) height of projectile?

7.A ball is raised from the top of a tower of height h. It takes T seconds to reach the ground.

What is the position of the ball in T/3 seconds?


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8.Define average velocity. A car moves from station A to station B with a velocity of 40 km/h

and back with a velocity of 60 km/h. Find the average velocity.

9.Define the dot product of two vectors.

Find whether he two given vectors are perpendicular or not.

A=5i-2j+k B=6i+7j-9k

10.The ceiling of a long hall is 25 m high. What is the maximum horizontal distance hat a ball

thrown with a speed of 40 m/s can go without hitting the ceiling of the hall?

11.A car at rest accelerates uniformly to a speed of 144 km/h in 20 s. How much distance is

covered by the car?

12.Prove that the maximum horizontal range is four times the maximum height attained by a

projectile, which is fired along the required oblique direction.

13.State the triangular law of vector addition.

14.A stone tied to the end of a string is whirled in a horizontal circle. If the string breaks, the

stone flies away tangentially. Why?

15. Draw the v-t graphs for (i) uniform accelerated motion (ii) uniform retarded motion.


1.A ball is thrown vertically upwards with 20m/s from the top of a building of height 25m.How

high will the ball rise? How long will it take it take to hit the ground?

2.Prove that the distances traversed during equal intervals of time by a body falling rest, stand to

one another in the ratio 1:3:5:7

3.If a, b, c are the distances move by a particle with a constant acceleration during the lth

, nth

,

mthsecond of motion of the body respectively. Show that a( m-n ) + b( n-l ) +c( l-m ) = 0

4. How is the velocity time graph of the uniformly accelerated motion helpful in studying the

motion of the body in one dimension?

5. A motorboat is racing towards north at 25 km/ hr and the water current in that region is 10

km/hr 60 east of south. Find the resultant velocity of boat

6. If A and B form two sides of a parallelogram then prove that the area of parallelogram is A X

B.


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7. A footballer kicks a ball at 30 with 20 m/s Calculate (i) the time at which the ball reaches the

highest point, (ii) horizontal range, (iii) maximum height

8. The radius of the earths orbit around the sun is 1.5 X 1011

m Calculate angular and linear

velocity of earth. Through how much angle does the earth revolves in 2 days.

9.A cyclist is riding with 54 km/hr .on approaching a circular turn of 50 m he applies brakes and

reduces his speed at the rate of 1m/s every second. What is the magnitude and direction of the

net acceleration of the cyclist on the circular track.

10. A boy standing on the edge of a cliff 980 m above the ground and throws a stone horizontally

with an initial speed of 20 m/s. find the time taken by the stone to reach the ground and the speed

at which it hits the ground.

Long Answer Questions ( 5 Marks each)

1.Prove the three equations of motion by calculus method.

A particle experiences constant acceleration for 20 s after starting from rest. If it travels a

distance x in the first 10 seconds and y in the next 10 seconds, find the relation between x and y.

2.What do you mean by projectile motion? Explain with examples. Obtain the expression for

the time of flight and the range of projectile.

3.State the two laws of vector addition. Give analytical treatment for finding its resultant when

both are inclined at an angle .

A man is walking on a level road at a speed of 3 km/h. Rain is falling vertically with 4km/h.

Find the velocity of the rain wrt the man.

4.Given A=4i+6j-9k and B=6i-8j +8k.Find their addition, subtraction, dot product and cross

product.

Rain is falling vertically with35m/s. Wind starts blowing after sometime with 12m/s in east to

west direction. In which direction should a boy waiting at a bus stop hold his umbrella?

5.What do you mean by resolution of a vector? Give two examples. A bird moves with a

velocity of 20 m/s in a direction making an angle of 60 with a eastern line and 60 with a vertical

upward. Represent the velocity vector in rectangular form.

6. Define centripetal force. Derive an expression for the centripetal acceleration of a body

moving with uniform speed along a circular path. Explain how it acts along the radius towards

the centre of the circular path.


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7.What do you mean by relative velocity? Explain graphically. Rain is falling vertically with

speed 50m/s. A girl rides a cycle with 20m/s in east to west direction. In which direction should

she hold the umbrella?

8.Draw the v-t graph for a uniform accelerated motion. Show that area under the graph and time

axis is equal to the distance covered by the object in that interval.

9.Find the expression for distance covered by a body in nth

second. A rocket is fired vertically

from the ground with a resultant vertical acceleration of 10m/s. The fuel lasts for 60s and it

continues to move up. What is a maximum height reached?

10.What is uniform circular motion? Obtain the relation between linear and angular velocity. A

body of mass 10kg revolves in radius 20cm and makes 1000 revolutions per minute. Calculate

linear velocity, angular velocity, time period, centripetal acceleration. and the centripetal force.

Unit:3

LAWS OF MOTION

Weightage-6


1. Give the magnitude and direction of the net force acting on

(a) a drop of rain falling down with a constant speed,

(b) a cork of mass 10 g floating on water,

(c) a kite skillfully held stationary in the sky,

(d) a car moving with a constant velocity of 30 km/h on a rough road,

(e) a high-speed electron in space far from all material objects, and free of electric and magnetic

fields.

2.Define one Newton.

3. Why an athlete runs some steps before taking a jump?

4. How does friction help in walking?

5. Give the relation between Newton and dyne.


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6. A body moving over the surface of another body suddenly comes to rest. What happens to the

friction between the surfaces?

7. The forces of action and reaction are equal in magnitude and opposite in direction. But they

do not balance each other. Why?

8. Why does water does not fall when a bucket full of water is rotated in a vertical circle?

9. There is a limit beyond which the polishing of a surface increases frictional resistance rather

than decreasing it. Is it true?

10. Is a single isolated force possible in nature?

11. Heavier bodies need greater initial effort to put them in motion. Why?

12. An impulsive force of 100 N acts on a body for 1 s . What is the change in its linear

momentum?

13.Calculate the net force acting on a body o mass 10 kg moving with a uniform velocity of 2

m/s.

14. A soda water bottle is falling freely. Will the bubbles of the gas rise in the water of the

bottle?

15. A person sitting in the compartment of a moving train moving with uniform speed throws a

ball in the upward direction. What path of the ball will appear to him? What to a person

standing outside?


1. Explain the need of banking of tracks.

2. Derive an expression for the apparent weight of a person in a lift when

(a) The lift is moving up with acceleration

(b) Moving down with acceleration

(c) Moving up with acceleration

(d) Moving down with deceleration

(e) Moving up or down with constant velocity.


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3. A light body and a heavy body have the same momentum which of the two bodies will have

greater kinetic energy?

4. The momentum of a body increases by 20%. What is the percentage increase in kinetic

energy?

5. A worker pulls a 200 N packing crate with an applied force of 55.0 N. The crate accelerates at

a rate of 0.250 m/s (squared). What is the coefficient of kinetic friction between the crate and the

factory floor?

6. A 200 N crate rests on a ramp; the maximum angle just before it slips is 25 degrees with the

horizontal. What is the coefficient of static friction between the crate and the surface of the

ramp?

7. A man pulls a sled with a weight of 200 N with a constant velocity across a horizontal snow

surface. If a force of 80N is being applied to the sled rope at an angle of 53 to the ground, whatis the coefficient of friction between the sled and the ground?

8.A jet plane is flying with a constant speed along a straight line at an angle of 30 above thehorizontal. The weight of plane is 86 500N. Its engine provides a forward thrust T of 103 000N.

The lift of force L(directed perpendicular to the wings)and the force R of air resistance(directed

opposite to the motion)act on the plane. Find L & R

9.A student pulls a 150. N sled up a 28slope at a constant speed by applying a force of 100. N.

Near the top of the hill he releases the sled. With what acceleration does the sled go down thehill?

10. What is inertia? Explain the three types of inertia.

11. Explain the self adjusting nature of friction with the help of a graph.

12. Give some methods to increase and decrease friction.

13. What is Atwoods machine? Derive an expression for the acceleration and the tension.

14. Discuss the motion of a body in a lift. What is weightlessness?

15. State the laws of static friction. Define the term coefficient of friction.


1.State the three laws of motion.

2. Show that the second law of motion is the real law of motion.


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3.How do you account for the (i) function of mud guards and the (ii) function of shockers in a

scooter?

4.What are the three types of inertia? Give at least two examples of each type.

5.Discuss some practical application of the principle of conservation of linear momentum.

6.Discuss the apparent weight of a person in an elevator.

7. State the laws of static friction. And hence define the coefficient of friction.

8.A bullet of mass 0.05 kg moving with a speed of 70m/s enters a heavy wooden block and is

stopped after a distance of 40cm.Calculate the average resistive force exerted by the block on the

bullet.

9.Why the roads are banked? Define angle of banking and obtain its expression.

10.Why does a cyclist bend while taking a circular turn? Obtain the angle of banking.

Long Answer Questions ( 5 Marks Each)-

1. What do you mean by impulse of a force? Show that this is equal to the product of the

average force and the time interval for which the force acts. Discuss some f the applications of

this concept.

2. Define the terms static friction, limiting friction and kinetic friction. Show that static friction is

self adjusting force with the help of a graph.

3. What is banking of roads? Deduce the expression for the angle of banking .A train of mass

106kg rounds an unbanked circular bend of radius 20 m at a speed of 72 km/h. What provides the

centripetal force for this purpose? Calculate the angle of banking required to prevent the wear

and tear of the tyres.

4. Obtain the expression for the acceleration of a body sliding down an inclined plane.A mass of 5kg rests on an incline plane of 30.If the coefficient of friction is 1/3, find the least

force, acting parallel to the plane (i) to keep the mass from sliding down (ii) to move the mass upthe plane..

5. State Newtons third law of motion. Use this to prove the principle of conservation of linear

momentum. Why does a gun recoil? Explain.

6. What do you mean by the impulse of the force? Give its two applications from daily life.

Show that it is equal to the product of the average force and the time interval for which the force

acts.


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A ball of mass 150g moving with the velocity of 15 m/s is brought to rest by a player in 0.05 s

Calculate the impulse and the average force exerted by the player.

7. Define angle of friction and angle of repose. Show that both are numerically equal.

8. Give some important applications of the third law of motion.

Briefly explain how a horse is able to pull a cart.A bullet of mass 0.04 kg moving with the speed of 90m/s enters a heavy wooden block and is

stopped after a distance of 60 cm. What is the average resistive force exerted by the block on the

bullet?

9.Find the expression for the work done in sliding a body (i) over a rough horizontal surface. (ii)

Up an inclined plane.

Determine the maximum acceleration of the train in which a box lying on the floor will remain

stationary, if the coefficient of friction between the box and the trains floor is 0.15.

10. Friction is a necessary evil. Explain.Also explain,

(i)Why it is easier to pull a lawn roller than to push it?.

(ii)How does a horse pulls a cart?

Unit:4

WORK,ENERGY AND POWER

Weightage-6


1.If mass of the moving body is much greater than the mass of the body at rest than what is the

approximate velocity of the moving body after head-on collision?.

2. At what point the potential energy of a body is taken to be zero?

3. Does the work done on a body by force depend upon the path followed by it?

4. If a body hits the ground from height h1and rebounds to a height h2after having inelastic

collision with the ground then what is the coefficient of restitution?

5. A body hits the ground with 50m/s velocity and has inelastic collision with the ground then

with what velocity it will rebound if the coefficient of restitution is 0.2.

6.A body at rest explodes in three fragments. Is it possible that two equal parts move in mutually

perpendicular directions with the same velocity and third mass moves midway between the two?

7.Can the kinetic energy be increased without applying external force?


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8. What is the nature of energy associated with a bird flying in air?

9. What is the work done by an electron revolving around an atom?

10. A moving car suddenly stops. Is its momentum destroyed?

11.A porter moving vertically up the stairs with a suitcase on his head. Is he doing work?

12. Can a body have energy without momentum?

13.Can a body have energy momentum without energy?

14 How does the kinetic energy of a body changed if its momentum is doubled?

15.How does the momentum of a body changed if its kinetic energy is doubled?

Short

Answer

Questions

(

2

Marks

each)

1.A ball is dropped from rest at a height of 20m. If it loses 30% of its kinetic energy on striking

the ground, what is the height to which it bounces? How do you account for this loss in kinetic

energy?

2.Why is no energy being consumed in planetary motion? Explain.

3.Two ball bearings of mass m each moving in opposite directions with equal speed v collide

head on with each other. Predict the outcome of the collision, assuming it to be perfectly elastic.

4.If a body is dropped from a height of 40m then after 3 inelastic collisions with the ground to

which height the body will rise? (Given: Coefficient of restitution = 0.5)

5.A truck and a car are moving with the same K.E. on a straight line road. If their engines are

made off at the same time, which one of them will stop at a lesser distance?

6.The power of a pump motor is 4KW. How much water in kg/minute can it raise a height of

20m? (g = 10 m/s2)

7. A rod of length 3m is suspended vertically from a fixed point. It is given an angular

displacement of 60 in the vertical plane. If its mass per unit length is 2 kg then find the work

done?

8. When a mass m2 is at rest and mass m1 moving with velocity u1hits it elastically, show that the

fraction of the momentum transferred to the mass at rest is 2n/(1 + n) where n is ratio of the

masses.

9. Is it possible for work to be positive negative or zero? "Explain with example.


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10.The bob of a simple pendulum is released from a horizontal position. If the length of the

pendulum is 2m, what is the speed with which the bob arrives at the lowermost point? Given that

it dissipates 10% of its initial energy against air resistance?

11 Give the various gravitational units of work. Give their relations also.

12.What is 1 e.V(electron volt)?Give its values in Joules. Give values of 1 MeV and 1 BeV also.

13.When water is flowing through a pipe then its velocity changes by 5%, find the change in the

power of water?

14.The kinetic energy of rushing out water from a dam is used in rotating a turbine. The pipe

through which water is rushing is 2.4 meters and its speed is 12 m/sec. Assuming that whole of

kinetic energy of the water is used in rotating the turbine, calculate the current produced if

efficiency of the dynamo is 60% and the station transmits power at240 kV. Density of water =

103kg/m

3.

15.If a body of mass 2kg is at rest and is hit by a mass of 4kg moving with 3m/s, find fraction of

the momentum retained by the moving body assuming the collision to be elastic and head-on.

Short Answer Questions ( 3 Marks Each)

1.If the speed of a moving vehicles increased by 200% then how much should be the change in

the retarding force to stop the vehicle over half the previous distance?

2. If 20 Joules of work is done in compressing spring from 0 cm to 6 cm then find the work done

in compressing the same from3cm to 6 cm.

3. A car and a truck are moving with same kinetic energy. They are stopped by applyingsame retarding force. Which one will stop at a smaller distance?

4. Define a collision. What are the two types of collision? Define the term coefficient ofrestitution.

5. Illustrate with he help of a graph, how the mechanical energy is conserved in a vibrating

simple pendulum?

6. Establish a relation between kinetic energy and linear momentum. Plot the following

graph. (i) kinetic energy vs mass (ii) momentum vs mass (iii) kinetic vs momentum.

7. What are conservative and non conservative forces? Illustrate with examples.

8.When an automobile moving with the speed of 36km/h reaches an upward incline road of

angle 30, its engine is switched off. If the coefficient is 0.1, how much distance will the

automobile move before coming to rest?


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9.A short travelling at the rate of 100 m/s is just able to pierce a plank 4 cm thick. What

velocity is required to just pierce a plank 9cm thick?

10.A bullet of mass 12g and horizontal speed of 50 m/s strikes a block of wood of mass 450gand instantly comes to rest with respect to the block. The block is suspended from the ceiling

by means of thin wires. Calculate the height to which the block rises.

Long Answer Questions ( 5 Marks Each)-

1.State and prove the work-energy theorem.A ball at rest is dropped from a height of 12m .It loses 25 % of its kinetic energy in striking the

ground. Find the height to which it bounces.

2.Show that the total mechanical energy of a body falling freely under gravity is conserved.Also plot the graph.

A bullet of mass 50 g is fired with 200m/s on a soft plywood of thickness 2.00cm.The bulletemerges only with 10% of its initial kinetic energy. What is the emergent speed of the bullet?

3.Define elastic collision and discuss it for two bodies colliding elastically head-on in one

dimension. Calculate the velocities of bodies after collision.A ball moving with the speed of 8 m/s strikes an identical ball such that after the collision the

direction of each ball makes an angle 30 with the original line of motion. Find the speeds of

the two balls after the collision.

4.What are conservative and non conservative forces? Illustrate with examples.

A shot traveling at the rate of 100m/s is just able to pierce a plank 4cm thick. What should bethe velocity of the bullet if it has to just pierce a plank of 9 cm?

5.Obtain the relation between linear momentum and kinetic energy.

(i) If the linear momentum increases by 20%, what will be the % increase in the kineticenergy?

(ii)The masses 1g and 4g are moving with equal kinetic energies. Calculate the ratio of their

linear momenta.

6.Explain what is meant by potential energy of a spring? Obtain an expression for it and

discuss the nature of its variation.A block of mass m moving at a speed of v compresses a spring through a distance x before its

speed is halved. Find the spring constant of the spring.

7.Two masses are released from their positions. Calculate the velocity with which the mass of

5 kg touches the surface if its initial height from the surface is 4m. Also, show that the gain in

KE of the system is equal to loss in its PE


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.

8. Illustrate with he help of a graph, how the mechanical energy is conserved in a vibratingsimple pendulum?

The mass of a pendulum bob is 0.2 kg, and it is suspended by a string 1m long. It is pulled

aside until the thread is at 30 to the vertical. How much work is done? The bob is nowreleases. Find its KE at the lowest point.

9.What do you mean by elastic collision in two dimensions?Show that in perfectly elastic collision in two dimensions between two particles of same mass,

the two particles move along mutually perpendicular directions after the collision.

10 How will you justify that hydro-electric power plant is an illustration of law of

conservation of energy?

The turbine pits at the Niagra falls are 50 m deep. The average horse power developed is 5000,the efficiency being 85 %. How much water passes through the turbines per minute?

Unit:5

RIGID BODIES AND ROTATIONAL MOTION

Weightage-6


1. What is the position of the centre of mass of a uniform triangular lamina?

2. What is the moment of inertia of a sphere of mass 20 kg

and radius1/4

about its diameter?

3. A cat is able to land on its feet after a fall. Explain the principle.

4. What is the value of linear velocity if w =3i+ 4j-9k and r =5i- 6j +6k?

5. Two particles in an isolated system under go head on collision. What is the acceleration of the

centre of mass of the system?

6. Which component of a force does not contribute towards torque?


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7. What is the position of centre of mass of a rectangular lamina?

8. Which physical quantity is represented by the product of moment of inertia and angular

velocity?

9. What is the angular velocity of the earth spinning about its own axis?

10. Name the constant whose dimensions are same as that of angular momentum.

11.Whet there is no external torque acting on a rotating body, which of the following quantities

can change?(i) angular acceleration (ii) angular momentum (iii) angular speed.

12.Two discs of same mass and thickness are made of materials having different densities.

Which one of them will have larger moment of inertia?

13.If earth were to shrink suddenly, what would happen to the length of the day?

14. A disc of metal is melted and recast in the form of a solid sphere. What would happen to the

moment of inertia about a vertical axis passing through the centre?

15. Is radius of gyration of a body constant quantity?


1 Show that the moment of couple does not depend on the point about which you take the

moments.

2. Obtain the relation between torque and angular momentum.

3. Show that for an isolated system the centre of mass moves with uniform velocity along a

straight line path?

4. The angle covered by a body in rotational motion is give by the equation = 6t +5t2+ 2t

3.

Determine the value of instantaneous angular velocity and angular acceleration at time t = 2s.

5. Establish the third equation of rotational motion.

6. Find the expression for radius of gyration of a solid sphere about one of its diameter?

7. Prove that the centre of mass of two particles divides the line joining the particles in the

inverse ratio of their masses?

8. A circular ring of diameter 40cm and mass 1kg is rotating about an axis normal to its plane

and passing through the centre with a frequency of 10 rotations per second. Calculate the angular

momentum about its axis of rotation?

9. State the theorems of moments of inertia.


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10. State and prove the law of conservation of angular momentum.

11. What do you mean by? (i) torque (ii) angular momentum (iii) moment of inertia

(iv) radius of gyration

12. A hoop of radius 2 m weighs 100 kg. It rolls along a horizontal plane with 20 m/s. How

much work has to be done to stop it?

13. Four masses 1, 2, 3 and 4 kg are situated at the four corners of a square of side 4m .Locate

the centre of mass.

14. State the principle of moments of forces.

15. What is couple? Explain.


1. Establish a relation between kinetic energy of rotation and the moment of inertia of a rigid

body.

2. Derive an expression for the moment of inertia of a ring about an axis passing through the

centre and perpendicular to the plane.

3. Establish a relation between torque and moment of inertia of a rigid body.

4. What will be the duration of the day if the earth suddenly shrinks to 1/64 of its original

volume?

5. A disc of mass 5 kg and radius 50 cm rolls on the ground at the rate of 10 m/s. Calculate the

kinetic energy of the disc.

6. Energy of 484 J is spent in increasing the speed of a flywheel from 60 rpm to 360 rpm.

Calculate the moment of inertia of the flywheel.

7. Give some examples on the law of conservation of angular momentum.

8. What is the physical significance of the moment of inertia of a body? State the factors on

which it depends.

9. Briefly explain equilibrium of a rigid body. When is a body said to be in partial equilibrium?

10. A car weighs 1500 kg. The distance between its front and back axles is 2m. Determine the

force exerted by the level ground on each front wheel and each back wheel, if the centre of

gravity is 1.00m behind the front axle?


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Long Answer Questions ( 5 Marks Each)

1. (i)Briefly discuss the concept of moment of force. Obtain its relation with moment of inertia

(ii) If angular momentum moment of inertia is decreased, will its rotational K.E. be also

conserved? Explain.

2.(a)What do you mean by radius of gyration of a body? Calculate the radius of gyration of a

cylindrical rod of mass m and length l about an axis of rotation perpendicular to its length and

passing through the centre.

(b) Which physical quantities are represented by the (i) Rate of change of angular momentum

(ii) Product of I and w

(c) Find the angular momentum of a satellite of mass m revolving around the earth having mass

Mein an orbit of radius r.

3. Define centre of mass of a system. Derive its expression for a two particle system.

Three masses 1, 2, 3 kg are situated at the three corners of an equilateral triangle of side 4m

.Locate the centre of mass.

4. Discuss the physical meaning of angular momentum. Prove that the angular momentum of a

system is twice the product of its mass and areal velocity. How does it lead to Keplers second

law of planetary motion?

5. Define the term moment of inertia. Obtain the expression for the moment of inertia of a

circular disc about an axis passing through its centre and perpendicular to its plane and also

about its diameter.

6. Obtain the expression for the linear acceleration of a cylinder rolling down an inclined plane

without slipping. A ring, hollow cylinder and a solid sphere of same mass and radius are allowed

to roll down an inclined plane without slipping. Which will reach the bottom first? Which of the

bodies will reach with maximum velocity?

7. State and prove the theorems of moment of inertia. Four masses 1, 2, 3 and 4 kg are situated atthe four corners of a square of side 4m .Find the moment of inertia of the system about its

anyone side.

8. State the laws of rotational motion.

The moment of inertia of a body about a given axis is 1.2 kg/m2. Initially the body is at rest. In

order to produce a rotational KE of 1500J, for how much duration, an acceleration of 25 rad/s2

must be applied about that axis?


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9. Establish a relation between torque and angular acceleration.

What constant torque should be applied to a disc of mass 10 kg and diameter 50 cm so that it

acquires an angular velocity of 2rad/s in4s? The disc is initially at rest and rotates about an axis

through the centre of the disc and in a plane perpendicular to the disc.

10. (i) Equal torques are applied on a cylinder and a hollow sphere. Both have same mass and

radius. The cylinder rotates about its axis and the sphere rotates about one of its diameters.

Which will acquire greater speed? Explain.

(ii) A solid disc and a ring both of radius 10 cm are placed on a horizontal table simultaneously,

with initial angular speed 31.4 rad/s .Which of them will start to roll earlier? The coefficient of

kinetic friction is 0.2.

UNIT: 6

GRAVITATION

Weightage-5


1. Why is gravitational potential energy negative?

2. What is geosynchronous satellite?

3.Define orbital velocity.

4.How much is the torque due to gravity on a body about its centre of mass.

5 What is the time period of a simple pendulum at the centre of the earth?

6.Where does a body weigh more-at the surface o the earth or in a mine?

7.Which has greater escape velocity-Mercury or Jupiter?

8 The escape velocity from the earth for a body of 20 g is 11.2 m/s. What will be its value for a

body of 100 g?

9 Two artificial satellites are revolving round the earth, one closer to its surface and other away

from it. Which has larger speed?

10.Does the speed of a satellite remain constant in an orbit?


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11.Will one kg sugar be more at the poles or at the equator?

12.The centripetal force on a satellite revolving around the Earth is F. What is gravitational forcedue to Earth on it/

13.Can a pendulum vibrate in an artificial satellite?

14.If Earth be at 1 half its presence distance from the sun, how many days will there be in a year?

15.Two satellites of masses 3m and m orbit the Earth in circular orbits of radii r and 3r

respectively. What is the ratio of their orbital speeds?

Short Answer Questions( 2 Marks each)

1.Derive an expression for the orbital velocity.

2.Define acceleration due to gravity. Show that the value of g decreases with altitude or height.

3.State the conditions necessary for a satellite to appear stationary

4.Derive an expression for the escape velocity of a satellite projected from the surface of the

earth.

5.What is the maximum value of potential energy that can be possessed by a heavenly body?

Give the general expression for potential energy of an object near the surface of earth

6.State Keplers law of planetary motion. Deduce Newtons law of gravitation from Keplerslaw.

7.Explain the variation of acceleration due to gravity with (a) altitude (b) depth.

8. What do you mean by weightlessness? Give two examples.

9.Define gravitational field and intensity of gravitational field.

10.If the diameter of the earth becomes two times its present value ,then how would the weight

of an object on he surface be affected?

11.Imagine a spacecraft going from the earth to the moon. How does its weight vary as it goes

from the earth to the moon? Will there be any change in its mass?

12.Obtain the expressions for orbital velocity, time period of a satellite.\


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13.What do you understand by gravity and acceleration due to gravity. Establish a relation

between g and G.

14.Explain how the knowledge of small g helps us to find the mass of the Earth.

15. Explain the Cavendish experiment to measure the value of G.


1.How much below the surface of Earth does the g reduces to 36% of its value on the surface of

the Earth.

2.What is the gravitational intensity. Calculate it at the surface of the moon given mass of the

moon is 7.34 x 1022

kg and the radius is 1.74x106

m.

3.Explain the reduction of Keplers 2nd

law and 3rd

law of planetary motion.

4.Discuss the variations of g with depth. At what height from the earth surface g is the same at a

depth 160 km below the surface of the Earth.

5.Obtain the expression for gravitational potential energy.

6.Two heave spheres each of mass 100 kg and 0.10m radius are placed 1m apart on a horizontal

table. What is the gravitational force and potential at the midpoint of the line joining the centers

of the spheres?

7.What do you understand by intensity of gravitational field. Prove that gravitational intensity at

a point is equal to the acceleration due to the gravity at the point.

8.Explain gravitational potential and gravitational potential energy of a body . Establish a

relation between them .

9.What is the minimum energy required to launch a satellite of mass m from the surface of Earth

of mass M and radius R in a circular orbit oat an altitude 2 R.

10.Find the percentage decrease in the weight of the body when taken to a height of 16 km above

the surface of the earth.

Long Answer Questions(5 Marks each)

1.State and prove Keplers laws of planetary motion.


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2.Define escape velocity and derive an expression for the escape velocity of a body from the

surface of earth.

3.Give some properties of gravitational force.A rocket is fired from the earth towards the sun. At what point of its path is the gravitational

force on the rocket zero?

4.Define the term gravitational potential and obtain its expression.

Two bodies of masses M and m are r distance apart. Find the potential at the position where the

gravitational field due to them is zero.

5.Explain the variation of g with the altitude with the help of a graph.

At what height above the earth surface the value of g is half of its value on earths surface?

6.Define orbital velocity and obtain its expression.Show that the moon would depart for ever if its speed were increased by 42%.

7.Discuss the Principle of launching of a satellite .What are geostationary satellites? Find at

what height above the earths surface does a satellite is geostationary.

8.Obtain Keplers second law from Newtons law of gravitation. The distance of Jupiter from the

Sun is 5.2 times that of the earth. Find the period of revolution of Jupiter around the sun

9.What is binding energy of a satellite? Obtain its expression. Calculate the change in

gravitational potential energy when a body of mass m is raised to a height nR above the surface

of the earth of radius R?

10.Three particles, each of mass m are placed at the vertices of an equilateral triangle of side a.

What is the gravitational field and gravitational potential at the centroid of the triangle?

UNIT: 7

BULK PROPERTIES OF MATTER

Weightage-10


1.How does the Youngs modulus change with the rise in temperature?

2.Why are electric poles given hollow structure?

3.The length of a metal is l1, when the tension in it is T1and l2, when the tension is T2.Find the

original length of the wire.


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4 A wire stretches a certain amount under a load. If the load and diameter are both increased

to three times, find the stretch caused in the wire.

5 What is more elastic: water or air, Why?

6. What is the value of Youngs modulus for a perfectly rigid body?

7 The length of a wire is cut to half. What will be the effect on the increase in its length, under a

given load?

8. Two wires are made of same material. The length of the first is half that of the second wire

and its diameter is double that of the second wire. If equal loads are applied on both wires, find

the ratio in their lengths. (Ans. 1:8)

9. Which state of matter has volume elasticity?

10. Which type of strain is there, when a spiral spring is stretched by a force?

11 What is the internal force of a liquid known as?

12 Which fundamental law forms the basis of equation of continuity?

13.Why oils of different viscosities are used in different seasons?

14.The clothes are better cleaned with hot water than with cold water. Why?

15 Write the dimensional formula and S.I unit of compressibility.


1.What is Poissons ratio?

2 When wax is rubbed on cloth, the cloth becomes water proof. Why?

3.What do you mean by surface tension At what temperature, the surface tension of a liquid is

zero?

4. What is the terminal velocity? What is the terminal velocity of a body in a free falling system?

5 A load of 2 kg produces an extension of 1mm in a wire of 3m in length and 1mm in

diameter. Calculate the youngs modulus of elasticity of the wire.


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6. What force is required to stretch a wire of steel 1 sq.cm in cross section to double its length? Y

of steel = 2 x 1011

Nm-2

7. A stress of 1kg /sq mm. is applied to a wire of which Youngs modulus is 1011Nm

-2.Find the

% increase in its length.

8 A tank 5 meter high is half filled with water and then filled to the top with oil of density 0.85

g/c.c. What is the pressure at the bottom of the tank due to these liquids? (4.5325 x 104N/m2)

9 When 0.15 kg of ice at 0C is mixed with 0.5 kg of water at 40 C in a container the resulting

temperature is 5 C. Calculate the heat of fusion of ice.

10 A U tube contains water and methylated spirit separated by mercury. The mercury columns inthe two arms are in level with 10.0cm of water in one arm, and 12.5 cm of spirit in the other.

What is the relative density of spirit? (0.8)

11 Explain the anomalous behaviour of water. Give its practical importance.

12 What are the three types of thermal expansions in solids? Establish a relation between them.

13 A wire ring of 30.0mm radius resting flat on the surface of the liquid is raised. The pull

required is 3.03 g f more, before the film breaks than it is after. Calculate the surface tension of

the liquid. (78.76 dyne/cm)

14.Calculate the energy evolved when 8 droplets of water (surface tension 0.072N/m) of radius

0.5mm each combined into one. (9.05 x 107 J)

15 Find the work done in blowing a soap bubble of surface tension 0.06 N/m from 2 cm radius to

5 cm radius. (0.003168 J)


1 Give reason for it?(i)Why does a spring balance show wrong measure after long use?

(ii) What is the advantage of the hydraulic system?

(iii)Why the girders are given I shape?

(iv) When a shaving brush is taken out of water its hair cling together. Why?

2 (a) Why does mercury drops its level in a capillary tube?

(b) If you double the radius of the capillary tube what will be the drop in height raise in the

tube?


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(c) If two row boats happen to sail parallel, and close to each other, they experience a force

which pulls them towards each other.

3 What do you mean by latent heat?

The water of mass 75 g at 100 C is added to ice of mass 20 g at - 15 C. What is the resulting

temperature? Latent heat of ice 80 cal / g , specific heat of ice 0.5.

4 Define angle of contact. What will be the effect of temperature on the angle of contact of a

liquid?

5. Show that the coefficient of area expansion of a rectangular sheet of the solid is twice its linear

expansitivity.

How much should the temperature of a brass rod to be increased so as to increase its length by1% Given for brass = 0.00002 / C

6 Discuss the three modes of heat transfer.

7 The volume of a metal sphere is 1000 cm3at 273 K. What would be its volume at 373K?

coefficient of linear expansion of the metal is 18 x 10-6

/K

8 (a) Plot Load Vs Extension curve for a metal on the graph and depicts :-

(i) Yield point, (ii) Breaking point,(iii)Elastic limit(iv) permanent set.

9. Two liquids of specific gravity 1.2 and 0.84 are poured into the limbs of a U-tube until the

difference in levels of their upper surfaces is 9 cm. What will be the heights of their respective

surfaces above the common surface in the U-tube? What is the pressure at the common surface?

(2520 N/m2)

10 State(i) Wiens displacement law (ii) Kirchhoffs law.

11What is thermal conductivity? State the factors on which it depends.

12. Explain the phenomenon.

(1) To keep a piece of paper horizontal, you should blow over and not under it.

(2) It is advised not to stand near a running train.

(3)Water is depressed in a glass tube whose inner surface is coated with paraffin wax. .

13.What is thermal expansion? Explain. Give its practical applications.

14. What do you mean by surface tension? Explain why small drops of mercury are spherical and

large drops become flat.


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15. Give reason

(i) The shape of meniscus of some liquids is plane, for some is concave and some is convex(ii). Oil spread over the surface of water

(iii)Put a piece of chalk into water. The chalk will emit bubbles in all directions

Long Answer Questions ( 5 Marks each)-

1 Explain the function of a venturimeter to find velocity of flow of liquid through a tube.

State the equation of continuity. Water flows through a horizontal pipe of varying cross sectional

area at the rate of 20 liters per minute. Determine the velocity of water at a point where diameter

is 4 cm. (0.2639 m/sec)

2 (i) Prove that the work done in stretching a wire = x tension x extension.

(ii) Prove that the work done per unit volume in stretching a wire for every type of strain = x

stress x strain.

(iii).State and explain Hooks law

A cube of aluminum each of side 4cm is subjected to a tangential force. The top face of the cube

is sheared through 0.012 cm with respect to the bottom face. Find (i) shearing strain (ii) shearing

stress and the shearing force.

Given:- =2.08 x 1011 dyne /cm2

3 Define surface tension and surface energy. Prove that the surface energy is numerically equal

to surface tension. Write the forces experienced by a sphere going down a vertical column of

liquid .Giving reason for the terminal velocity; derive an expression for terminal velocity.

4. . What are the factors affecting viscous force in a liquid flowing in a tube? Derive a relation

for the velocity up to which the liquid can have streamlined flow.

A liquid drop of diameter 4mm break into 1000 droplets of equal size. Calculate the resultant

change in the surface energy.

Surface tension of the liquid is 0.07 N/m.(3168 X10-8

J)

5. Explain hydrostatic paradox. Illustrate with an example. Discuss the variation of fluidpressures with depth. Hence explain how the Pascals law is affected in the presence of gravity.

6 Derive the excess of pressure inside a (i) liquid drop (ii) soap bubble. It is better to wash the

clothes in hot soap solution. Why?

How do insects run on the surface of water?

Calculate the force required to take away a flat plate of radius 5cm.from the surface of water

Given surface tension of water = 7210-3N/m. (0.022628 N)


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7. State the Newtons law of cooling and give is experimental verification.

8 State and prove Bernoullis theorem. What should be the properties of a liquid to satisfy

Bernoullis theorem? What are the limitations of Bernoullis Theorem?

9. What is the phenomenon of capillarity? Derive an expression for the ascent formula. What

will happen when the tube is of insufficient length? Explain. Why the tip of nib of a pen is split?

10 State and prove Torricelli theorem. Find the velocity of efflux of water from an orifice near

the bottom of a tank in which the pressure is 4.9x104N/m

2above the atmospheric pressure.

UNIT:8

THERMODYNAMICS

Weightage-5

Very Short Answer Questions( 1Mark Each)

1. What is an isochoric process?

2.On what factors does the efficiency of a Carnot engine depend?

3.State second law of thermodynamics. (Any one statement)

4.State zeroth

law of thermodynamics.

5.What is a heat engine?

6.Explain why a balloon is cooler after it bursts.

7.What is a PV diagram? What does the area between the PV curve and the volume axis

signify?

8.State the conditions for two bodies to be in thermal equilibrium.

9.Can the specific heat of a gas be infinity?

10.Is it possible to convert internal energy to work?

11.Can the temperature of an isolated system remain constant?

12.What is the nature of P-V diagram for an (i) isobaric process (ii)isochoric process?


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13.In summer, when the valve of the bicycle is removed, the escaping air appears cold. Why?

14.Which one among a solid, liquid and a gas of same mass and at same temperature, has the

greatest internal energy?

15.Can the efficiency of an engine be 100 %?


1.What is a cyclic process? Show that the work done in a cyclic process is equal to the areaenclosed by the loop representing the cyclic process.

2.Why gases have two principal specific heat capacities? Define them.

3.Why Cp> Cv? Prove that Cp Cv= R

4.Define the coefficient of performance of a heat pump.

5.A sample of gas (= 1.5) is compressed adiabatically from a volume of 1600 cm3to 400 cm

3.

If the initial pressure is 150 kPa, what are the final pressure and how much work is done on thegas in the process?

6.Write short notes on(i) Isothermal process

(ii) Adiabatic process.

7.Obtain the expression for the work done in an isothermal process

8.Two gases have the same initial pressure, volume and temperature. They expand to the same

final volume, one adiabatically and the other isothermally.

(a) In which case is the final pressure greater?(b) In which case is the work done greater?

(c) In which case is the final temperature greater?

9 State the first law of thermodynamics and use it to derive Poissons equation for an adiabatic

process.

10.400J of work is done on a gas to reduce its volume by compression adiabatically. What is the

change in internal energy of the gas?

11. Obtain the expression for the work done in an adiabatic process.

12.What are reversible and irreversible processes? Give two examples.

13.A certain gas at atmospheric pressure is compressed adiabatically to half its original volume.

Calculate the resulting pressure.


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14.Calculate the efficiency of a Carnots engine working between steam point and ice point.

15.Calculate the fall in temperature of helium initially at 15C,when it is suddenly expanded to8 times its original volume.


1.Write a short note on a Heat engine. Also give the block diagram.

2. What is a Refrigerator? Obtain its coefficient of performance.

3.Compare the isothermal and adiabatic process.

4.Define the terms-(i) System (ii) surroundings (iii) state variables (iv) Thermodynamic process

5.What do you mean by internal energy of a system? Explain.

6.A gram molecule gas at 127 C expands isothermally until its volume is doubled. Find the

amount of work done and heat absorbs.

8.Show that an adiabatic curve is always steeper than an isothermal curve.

9.One gram mole of an ideal gas at STP is subjected to a reversible adiabatic expansion to double

its volume. Find the change in internal energy in the process.

10.Calculate the efficiency of a Carnot engine working between 400Kand 350K.


1.State first law of thermodynamics and apply it to an isothermal process. Give its limitations

and hence state the second law of thermodynamics.

2.Explain the construction and various operations involved in a Carnots heat engine with neat

labeled diagram. Draw Carnots cycle and write expression for efficiency of a Carnots heat

engine.

3.State the three laws of thermodynamics (Zeroth law, first law and second law).Derive

Mayers formula.

4.Apply I law of thermodynamics to (a) isothermal process (b) adiabatic process.

An electric heater supplies heat to a system at the rate of 700W. If a system performs at a rateof 75 J/s, at what rate is the internal energy increasing

5 Derive an expression for the work done in an isothermal process.


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The work of 146J is performed in order to compress one kilo mole of gas adiabatically and in

this process the temperature of the gas increases 7C.Identify the atomicity of the gas.

6.During isothermal expansion of 800K, the working substance of a Carnot heat engine takes480 cal of heat. If the sink be at 300K,calculate,

(i) work done by the working substance during isothermal expansion

(ii)work done during isothermal compression.(iii)the efficiency.

7.State Kelvin-Planck statement for the second law of thermodynamics.The molar specific heat of Hydrogen is about (5/2)R in the temperature range of 250-750 K. At

lower temperatures the molar specific heat of Hydrogen decreases to about (3/2)R. At higher

temperatures, it tends to the value (7/2)R. What do you think is happening? Explain.

8.Define specific heats in gases. Why they have infinite values of specific heats? What are thetwo principal specific heats? Establish a relation between them.

9.What is a Refrigerator Define the coefficient of performance of a Refrigerator and obtain a

relation for it in terms of temperature T1and T2.Arefrigerator is to maintain eatables kept inside

at 9C,if the room temperature is 36C.Calculate the coefficient of performance.

10.What are the steps involved in Carnots heat engine?

State Carnots theorem and explain its significance.

UNIT:9

BEHAVIOUR OF PERFECT GAS AND KINETIC THEORY OF GASES

Weightage-5


1.Is the energy per mole of all gases (ideal) at a given temperature is the same?

2.Obtain the dimensional formula for R used in the ideal gas equation.

3.The absolute temperature of a gas be increased 3 times. What will be the increase in rms

velocity of the gas molecules?

4.Two different gases at the same temperature have equal rms. Is it true or false?

5.Give the characteristics of an ideal gas.


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6.Do the molecules of an ideal gas attract or repel each other? What about the molecules of a

real gas?

7.Are different hot gases such as nitrogen ,oxygen, at the same pressure and volume at the same

temperature?

8.What is the temperature at which the molecular motion ceases?

9.1cm3of hydrogen and 1 cm

3of oxygen are given at NTP. Which will have larger number of

molecules?

10.Can the temperature of a gas be increased keeping its pressure and volume constant?

11.Though velocity o air molecules is about 0.5km/s, the smell of scent spreads at a muchslower rate. Why?

12.Two identical cylinders at the same temperatures contain hydrogen at 2.5 atm and oxygen at

1.5 atm. If both the gases were filled in one of the cylinders, what will be the pressure?

13.On driving the scooter for a long time, the air pressure in the tyres slightly increases. Why?

14.Why cooling is caused by evaporation?

15.Define the degree of freedom

.Short Answer Questions (2 Marks each)

1.What is the ratio of r.m.s speed of oxygen and hydrogen molecules at the same temperature?

2.DefineMean free path, Absolute zero,

3.Abox contains equal number of molecules of hydrogen and oxygen. If there is a fine hole in the

box, then which gas will leak rapidly?

4.What are the degrees of freedom in a mono atomic, diatomic and tri atomic gases?

5.A gas is filled in a cylinder fitted with a piston at a constant temperature. Explain on the basis

of kinetic theory how the pressure of the gas increases by raising the temperature.

6.Mention the different ways of increasing the number of molecular collisions per unit time in a

gas

7.For an ideal gas the internal energy can only be translational kinetic energy


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8.Why there is no atmosphere on the moon.

9.Find an expression for an average kinetic energy(i)per gram mole and (ii)per molecule of a gas.

10.Explain why a gas cools on sudden expansion on the basis of kinetic theory of gasses.

11. Calculate the rms velocity of air molecule at NTP given 100 l of air at NTP weight 0.129 kg .

12.What is meant by Boltzmann constant. Calculate its value in SI unit.

13. The ratio of vapour densities of two gasses at the same temperature is 8:9. Compare the rms

velocities of their molecule.

14. Explain the phenomena of evaporation on the basis of kinetic theory of gasses.

15 If three molecules have speeds v1v2and v3, What will be there average and rms velocity.


1.Explain the concept of absolute zero on the basis of kinetic theory of gases. The

absolute temperature of the gas is increased 3 times. What will be the increase in root meanvelocity of the gas molecules? (0.732C).

2.Write the main postulates of kinetic theory of gases.

3.Deduce (i)Boyles law(ii)Charles law from kinetic theory of gasses.

4. Air is filled in a vessel at 60 C. To what temperature should it be heated in order that 1/3rd

of

the air may escape out of the vessel.

5.The pressure of the gas filled in a close vessel increases by 0.4% when temperature is increasedby 1 C. Find the initial temperature of the gas.

6. Calculate the rms of hydrogen molecules at NTP, the molecular weight of the hydrogen being

2.

7. Calculate the temperature at which the rms of gas molecules is doubled its value at 27C,

pressure of the gas remaining the same.


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8. Find the average kinetic energy of a molecule at 20C according to kinetic theory for mono

atomic and diatomic gases.

9. What is meant by Brownian motion? Explain the concept of mean free path.

10. From the kinetic theory explain the concept of pressure exerted by an ideal gas.


1.State the law of equipartition of energy. Use it to obtain the specific heat ratio of mono, di and

triatomic gases and hence define degrees of freedom.

2.(a) From Kinetic Theory of gases, explain kinetic interpretation of temperature and absolute

zero.

(b)Calculate the temperature at which root mean square velocity of SO2 molecules is the same as

that of the O2 molecules at 1270C.Molecular weight of O2 and SO2 are 32 and 64 respectively.

(5270C)

(c)At what temperature, pressure remaining constant, the r.m.s velocity of hydrogen be double

its value at N.T.P? (8190C)

3.Give the main points of kinetic theory of gases

Derive the expression for pressure exerted by an ideal gas in a container

4.Prove that the average kinetic energy of a molecule of an ideal gas is directly proportional to

the absolute temperature of the gas.

Find the temperature at which root mean square velocity of a gas is half of its value at 0C,

pressure remaining constant.

5.Explain the meaning of mean speed, rms speed and most probable speed

Four molecules of a gas have speeds 2,4,6,8 Km/sec respectively. Calculate (i) average and (ii)

root mean square speed. (iii) most probable speeds of a gas?

6.State and explain (i)Boyles laws (ii) Charles law from kinetic theory of gases. Why are theynot applicable to real gasses in all states?

7.State and explain (i)Gay lusscs law (ii)gas equation. Distinguish clearly between R and r for a

gas .Calculate the kinetic energy of hydrogen per g mole at 100 C.

8. Explain the Daltons law of partial pressures.

Show that rms of oxygen is root 2 times that of sulphur dioxide . Atomic weight of sulphur is 32

and oxygen is 16.


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9 Give the main postulates of kinetic theory of gases.

.Estimate the average thermal energy of a helium atom at (i) room temperature (ii)thetemperature on the surface of the sun.

10.What is Maxwells speed distribution and hence define most probable speed.

A flask contain argon and chlorine in the ratio 2:1 by mass . The temperature of the mixture is 27

degree c. Obtain the ratio of (i)average kinetic energy per molecule (ii) rms of the molecules of

two gasses. Give atomic mass of argon=39.9 u and molecular mass of chlorine is 70.9u.

. UNIT:10

OSCILLATIONS AND WAVES

Weightage-10


1.What is simple harmonic motion?

2.What will be the effect on time period, if the amplitude of a simple pendulum increases?

3.What is the function of water in the resonance apparatus? Can we use any other liquid?

4.Can a motion be periodic but not oscillatory?

5.Can a motion be oscillatory but not simple harmonic?

6.When are the velocity and acceleration in the same direction in S.H M?

7.Can we use a pendulum watch in an artificial satellite?

8.A girl is swinging in the sitting position. How will the time period affected if she stands up?

9.Will the pendulum clock lose or gain time when taken to the top of a mountain?

10.What will be the period of oscillation, if the length of a seconds pendulum is halved?

11 State the characteristic of the S.H.M.

12.Are all periodic motions oscillatory?


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11.Briefly explain the terms wavelength, frequency, time period and velocity of wave motion.

Establish relation between them.

12.Explain some significant properties of wave motion.

13.State the laws of vibration in a stretched string.

14. A steel rod 100cm long is clamped at the middle of it. The fundamental frequency of

longitudinal vibrations of the rod is given to be 2.53 kHz. What is the speed of sound in steel

(5.06 x 103m/sec?)

15.Obtain the equation of a plane progressive simple harmonic wave.

Short Answer Questions (3 Marks each)

1.Establish the relation between particle velocity and wave velocity

.

2. A string 1m long with mass 0.1gm/cm is under a tension of 400 Newton. Find the fundamentalfrequency. (100 Hz.).

3. Calculate the velocity of sound in a gas in which two wave lengths 2.04m produce 20 beats in6 seconds. (353.6 m/s).

4.Discuss the characteristics of stationary waves.

5.Audible frequencies have a range 40Hz. To 30,000 Hz. Express this range in terms of (1)

period T, (2) wavelength? In air, and (3) angular frequency, Give velocity of sound in air is 350m/s. (2.5 x 10-2s, 3.3 x 10-5s, 8.75m, 0.012m, 80? rad /second 60,000? rad /sec.)

6.If the splash is heard 4.23 seconds after a stone is dropped into a well, 78.4m deep, find the

velocity of sound in air. (340.87 m/sec)

7.Find at what temperature the velocity of sound in air will be 1 times the velocity at 11C

8.The velocity of sound in air at N.T.P is 331m/s . Find its velocity when the temperature rises to

910C and its pressure is doubled.(382.1m/s)

9.For the traveling harmonic wave, y = 2.0 cos[ 10t 0.0080x], where x and y are in cm. and t is

in sec. What is the phase difference between oscillatory motions at two points separated by a

distance of (1) 4m, (2) 0.5 m (3) /2 (4) 3/4.

10.Two tuning forks when sounded together produce 3 beats per second. On loading one of them

with a little wax, 20 beats are heard per second. Find its frequency if that of other is 386 Hz. (383

Hz.)


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11.A spring balance has a scale that reads 50 Kg . The length of the scale is 20 cm. A body,

suspended from this spring is when displaced and released, it oscillates with period of 0.60 s.

What is the weight of the body.(22.36 kgf)

.12.A spring of force constant 1200 N/m is mounted on a horizontal table .A mass of 3 Kg is

attached to the free end of the spring , pulled sideways to a distance of 2cm and released .(a)

What is the frequency of oscillation of the mass? (b) What is the maximum acceleration of themass? (c) What is the maximum speed of the mass?

13.The acceleration due to gravity on the surface of moon is 1.7 m/s2.What is the time period ofa simple pendulum on the moon if its time period is 3.5 sec on the earth?

(8.4 sec)

14.A pendulum clock normally shows correct time. On an extremely cold day, its length

decreases by 0.2%. Compute the error in time per day. (86.4%)

15.What do you understand by Simple Harmonic Motion? Explain its geometrical interpretation.The amplitude of a simple harmonic oscillator is doubled. How does this affect

(i) time period

(ii) total energy(iii) maximum velocity of the oscillator?


1.What are beats? Explain their formation analytically. Define beat frequency and beat period

Prove that the number of beats per second is equal to the difference between the frequencies ofthe two superposing waves.

2.Explain the relation respectively between displacement, velocity and acceleration with time in

S.H.M. graphically as well as theoretically.

.3.Find the total energy of a particle executing S.H.M. and show graphically the variation of P.E

and K.E with time in S.H.M. What is the frequency of these Energies w.r.t the frequency of

the particle executing S.H.M.

4.Explain the oscillation of a loaded spring and find the relations for the time period

and frequency in case of (i) horizontal spring (ii) vertical spring.

5.Distinguish between free, forced, and resonant oscillation with illustrations.

What is the time taken in S.H.M. to travel from x=A to x=A/2?

6.Show that the motion of a mass suspended by a spring is S.H.M, when it is displaced from its

mean position and released.

What is spring constant? Find its value in case of two springs connected in(i) series, (ii) parallel.


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7.What is a simple pendulum? Show that the motion executed by the bob of the pendulum is

simple harmonic. Derive an expression for its time period.

8. Obtain the expression for the velocity of the particle executing S.H.M. When is this velocity (i)maximum and (ii) minimum?

Derive Newtons formula for speed of sound in a gas .and apply Laplaces Correction?

9. What are harmonics? Discuss the formation of harmonics in a stretched string. Show that the

first four harmonics are in the ratio 1:2:3:4.

11.What are stationary waves? .Explain and draw the fundamental modes of vibration of

stationary waves in an open organ pipe.

A set of 24 tuning forks is arranges in series of increasing frequencies. If each fork gives 4 beats

with the preceding one and the last fork is octave of the first,

12.Explain and draw the fundamental modes of vibration of stationary waves in a closed organ

pipe.

Class 11- Physics

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