Practice Question paper for half yearly exam (PHYSICS)

Kendriya Vidyalaya Sangathan- Jaipur Region

Model Question Papers for Class XI

Half-Yearly Examination

Session-2016-17

Subject-Physics(042) This material was prepared under the patronage of

Dr. Jai Deep Das - Deputy Commissioner, KVS (RO) JAIPUR

Dr. V. Gowri - Asst.Commissioner,KVS(RO)JAIPUR

Sh. A. Jyothy Kumar- Asst. Commissioner, KVS (RO) JAIPUR

Dr. Sukriti Raiwani- Asst. Commissioner, KVS (RO) JAIPUR

Under the guidance of

Sh Om Parkash Yadav,Principal,

K.V.NO.2,EKLINGGARH,UDAIPUR

By the following Team

S.NO NAME OF THE PGT MODEL QUESTION PAPER NO.

1 SH LAXMAN SINGH

& SH ANIL KUMAR

MODEL QUESTION PAPER NO.-I

2 SH LAXMAN SINGH

& SH ANIL KUMAR

MODEL QUESTION PAPER NO.-II

3 SH LAXMAN SINGH

& SH ANIL KUMAR

MODEL QUESTION PAPER NO.-III

4 SH LAXMAN SINGH

& SH ANIL KUMAR

MODEL QUESTION PAPER NO.-IV

5 SH LAXMAN SINGH

& SH ANIL KUMAR

MODEL QUESTION PAPER NO.-V

Model Question Paper-I

Kendriya Vidyalaya Sangathan Half Yearly Examination

Class-XI Physics (Theory)

Time allowed: 3 hours MM: 70

Blue Print

S.No. Chapter/Unit

VSA

SA I SA II VBQ LSA Total

1 Mark 2 Marks

3 Marks 4 Marks

5 Marks

1 Physical World and Measurement

2 1 7

2 Kinematics 1 1 2 1 14

3 Laws of Motion 1 3 1 15

4 Work Energy and Power

1 1 1 1 11

5 Motion of System of Particles and Rigid

Body

1 2 1 12

6 Gravitation 2 3 11

7 Total 5(5) 5(10) 12(36) 1(4) 3(15) 26(70)

Model Question Paper-I Half Yearly Examination Class XI

PHYSICS (Theory)

Time: 3 Hrs. MM: 70

General instructions:

i. All questions are compulsory.

ii. There is no overall choice. However, an internal choice has been provided in one question of

two marks, one question of three marks and all three questions of five marks. You have to

attempt only one of the choices in such questions.

iii. Questions number 1 to 5 are very short answer type questions, carrying one marks each.

iv. Questions number 6 to 10 are short answer type questions, carrying two marks each.

v. Questions 11 to 22 are also short answer type questions, carrying three marks each.

vi. Question number 23 is value based question, carrying four marks.

vii. Questions 24 to 26 are long answer type questions, carrying five marks each.

viii. Use of calculators is not permitted. However, you may use log tables, if necessary.

G = 6.67 X 10-11

Nm2/kg

2 Mass of earth M = 6 X 10

24kg

Radius of earth R = 6.4 X 106m Acceleration due to gravity of earth g = 9.8 m/s

SECTION - A

1. Which component of velocity remains constant during motion of projectile?

2. An electron and proton possess same K.E. Which one has lesser momentum ?

3. What is the value of weight of a person at the Centre of the earth?

4. Why total energy of a satellite comes negative?

5. A retarding force is applied to stop a motor car .If the speed of the motor car is doubled, how

much more distance will it cover before stopping under the same retarding force?

SECTION - B

6. The Write an expression for the maximum error when the final result is the product of two

quantities .The length and breadth of a rectangle are (6 0.2) cm and (3 0.1) cm

respectively. Calculate the maximum error in the area of the rectangle.

7. (a). Name any two of physical quantities having no dimensional formula.

(b). 9.8m/s2

into cm/s2.

8. Find the unit vector which is parallel to the resultant of given vectors A=2i+j+4k and B=2i-

4j+2k .

9. State and prove work-energy theorem for a variable force.

OR

Define conservative and non-conservative force. Give one example of each?

10. Three masses 3kg, 4kg and 5kg are located at the corners of an equilateral triangle of side 1m.

Locate the centre of mass of the system.

SECTION - C

11. Define the term torque & angular momentum. Derive the relation between torque & angular

momentum of a body. Using it state law of conservation of angular momentum.

Define the term escape velocity. Derive expression for it in terms of mass and radius of a planet.

OR

Define the term orbital velocity. Derive an expression for it in terms of mass and the radius of

planet.

12. How does the acceleration due to gravity vary with the depth?

A body weighs 63N on the earth. What is the gravitational force on it due to earth at a height

equal to the radius of Earth?

13. State theorem of perpendicular axes for the moment of inertia of a body. Determine the

moment of inertia of a disc about any of its diameter (Given MOI of disc about axis through

center and perpendicular to its plane is ½ MR2 .

14. When a body makes ‘m’ moving with speed ‘v’ collides against another body of same mass at

rest, Prove that after elastic collision they move right angle to each other.

15. Explain that Newton’s second law of motion is the real law of motion.

16. Three blocks are connected together (as shown in the

figure) lie on a horizontal frictionless table and pulled to

the right with a force F= 60N.If m1=5kg, m2=10kg,

m3=15kg, find the tensions T1 and T2.

17. Draw velocity - time graph for uniformly accelerated motion starting with initial velocity ‘u’.

Derive the equation of motion v = u + at. And S = ut + ½ at2

18. State Parallelogram law of vector addition. Derive expressions for magnitude and

direction of the resultant.

19. State impulse-momentum theorem .A batsman deflects a ball by an angle of 300 without

changing its initial speed which is equal to 54 Km/h. What is the impulse imparted to the ball,

if the mass of the ball is 0.15Kg.

20. Find the percentage decrease in weight of a body when taken 16km below the surface of the

earth. Take the radius of the earth as 6400km.

21. Consider a simple pendulum, having a bob attached to a string that oscillates under the action

of force of gravity. Suppose that the period of oscillation of the simple pendulum depends on i.)

mass of the bob ii).length of the pendulum and iii).acceleration due to gravity ‘g’ at the place

.Derive the expression for its time period using the method of dimensions.

SECTION - D

22. .A physics teacher explained about conservation of Angular momentum in the class .After the

completion of her explanation she want to test how far how far the students are able to

understand the topic. In the process she selected two students by name Babita and Ram. Both

could explain the topic with examples..

(a) What qualities of them impress you?

(b) A physics teacher sits on a stool that is free to rotate nearly without friction about a vertical

axis .Her outstretched hands each hold a large mass so that the rotational inertia is 12kgm2.By

pulling her arms close to her body she is able to reduce her rotational inertia to 6 kg m2. If her

student starts spinning at 0.5 rad/s, what is her speed after she draws her arms in?

SECTION - E

23. What is banking of roads? Derive an expression for the maximum possible speed on a

road of banking angle θ and coefficient of friction μ between the road and the tyres.

Derive expression for optimum speed.

OR

(a). State the laws of limiting friction.

(b). A monkey of mass 40 Kg climbs on a rope which can stand a maximum tension of

600 N. In which of the following cases will the rope break. The monkey

(i) Climbs up with an acceleration of 6 m/s2

(ii) Climbs down with an acceleration of 4 m/s2

(iii) Climbs up with a uniform speed of 5 m/s

(iv) Falls down the rope nearly under gravity? (Take g= 10 m/s2)

(Ignore the mass of the rope) 2+3

24. Obtain the expression for time of flight, maximum height and horizontal range of a projectile

fired at an angle with the horizontal. An object is thrown with velocity 20m/s by making angle

of 30o with horizontal find the maximum height and time of flight ?

(g = 9.8m/s2).

OR

(a). Define the term centripetal acceleration. Derive an expression for its magnitude and

explain its direction.

(b) A gramophone disc rotates at 60rpm. A coin of mass 0.013 kg is placed at a distance of

0.08 m from its centre. Calculate the centripetal force acting on it.

26. (a) Show that total energy of freely falling object remain constant ?

(b) A cluster of clouds at a height of 1000m above the earth burst and enough rain fell to cover

an area of 106 square metre with a depth of 2 cm. How much work would have been done in

raising water to the height of the clouds? Given g = 980cm/s2 and density of water= 1gm/cm

3.

OR

Define power, also write its SI unit and dimension. A tube well pumps out 2400 kg of water per

minute. If water is coming out with a velocity of 3 m/s, what is the power of the pump? How

much work is done, if the pump runs for 10 hours?

Model Question Paper-II




Blue Print

S.No. Chapter/Unit

VSA


1 Mark 2 Marks

3 Marks 4 Marks

5 Marks


2 1 7

2 Kinematics 1 3 1 15



1 2 2 11

5 Motion of System of

Particles and Rigid Body

1 2 1 11

6 Gravitation 1 1 1 1 11

7 Total 5(5) 5(10) 12(36) 1(4) 3(15) 26(70)

MODEL PAPER-II

Kendriya Vidyalaya Sangathan Half Yearly Examination Class XI

PHYSICS (Theory)

Time: 3 Hrs. MM: 70


ix. All questions are compulsory.

x. There is no overall choice. However, an internal choice has been provided in one question of



xi. Questions number 1 to 5 are very short answer type questions, carrying one marks each.

xii. Questions number 6 to 10 are short answer type questions, carrying two marks each.

xiii. Questions 11 to 22 are also short answer type questions, carrying three marks each.

xiv. Question number 23 is value based question, carrying four marks.

xv. Questions 24 to 26 are long answer type questions, carrying five marks each.

xvi. Use of calculators is not permitted. However, you may use log tables, if necessary.

G = 6.67 X 10-11

Nm2/kg


24kg


SECTION - A

1 A mass is dropped from a certain height. At the same time another equal mass is thrown with a

horizontal velocity of u m/s. Which one of the two will reach the ground first?

2 A cricket player while catching the ball pulls his hand back. Why?

3 A car and truck are moving with the same kinetic energy on a straight road. Their engines are

simultaneously switched off. Which one will stop at a lesser distance?

4 Write two factors on which center of mass depends?

5 What is the height at which the satellite is to be parked for it to be a geostationary satellite?

SECTION - B

6 What are the dimensions of (i) power (ii) impulse (iii) surface tension and (iv) strain.

7 Define the power. Obtain expression for it in terms force and velocity?

8 Define escape velocity. Derive expression for the same.

OR

The value of acceleration due to gravity at the moon is 1/6 th of the value of g at the surface of

earth and diameter of moon ¼ th of the diameter of earth. Compare the ratio of their escape

velocity?

9 The factors affecting the time period of a simple pendulum are mass, length of pendulum and

acceleration due to gravity. Deduce the expression for time period of simple pendulum?

10 Work done by a force is given by W= F.S where F is force and S is displacement, Using this

expression show that

(i) Work done is also equal to change in kinetic energy

(ii) Work done is also equal to change in kinetic energy

SECTION - C

11 Derive an expression for the orbital velocity revolving in the orbit near the earth surface. How is

it related to escape velocity?

12 What do you mean by angular diameter? The sun’s angular diameter is measured to be 1920’’

.the distance D of the sun from earth is 1.496 x 1011

m. What is the diameter of the sun?

13 tate theorem of parallel axis. Three rings each of mass M and radius R are arranged as shown in

the figure. Find the moment of inertia of the system about YY axis. the moment of inertia of a

ring about its diameter is ½ MR2.

14 Write equation for the distance covered by uniform accelerated body in nth second. A body

travels half of its total path in last second of its fall from rest. Calculate its time of fall.

15 Show that in one dimensional elastic collision of two bodies, the relative velocity of separation

after collision is equal to relative velocity of approach before the collision.

16 At what angle two forces (P + Q) and (P - Q) act so that resultant is (i) √ (3P2 + Q

2) and (ii)

√2(P2 + Q

2).

17 Define relative velocity. Rain is falling vertically with speed of 10 √3 ms-1

.a man riding on a

bicycle is moving with speed of 10 ms-1

in north to south direction. What is the direction in

which he should hold his umbrella?

Or

Two bodies of masses 50kg and 150kg resp. are connected by a light string passing over a

smooth frictionless pulley. Calculate the acceleration of the masses and tension in the string.

18 State law of conservation of energy. Prove that the total energy of a freely falling body remains

constant at each and every point during its fall.

19 State law of conservation of momentum & prove it for two particle system using third law of

motion.

20 Define angle of friction and angle of repose .prove that coefficient of static friction is tangent of

angle of repose.

21 Three blocks are connected as shown in the figure on a smooth horizontal frictionless surface

and pulled to the right with a force of T3 = 60N. If m1 = 10kg, m2 = 20kg and m3 = 30kg, prove

that T1/T2 = 1/3.

22 Derive expressions for the moment of inertia of a uniform rod of mass M and length L about

an axis passing through the center of mass , perpendicular to its length

SECTION - D

23 A physics teacher explained about conservation of Angular momentum in the class .After the

completion of her explanation she want to test how far how far the students are able to

understand the topic. In the process she selected two students by name Babita and Ram. Both

could explain the topic with examples..

Answer these questions:-

(a) What qualities of them impress you?

(b) A physics teacher sits on a stool that is free to rotate nearly without friction about a vertical

axis .Her outstretched hands each hold a large mass so that the rotational inertia is

12kgm2.By pulling her arms close to her body she is able to reduce her rotational inertia to 6

kg m2. If her student starts spinning at 0.5 rad/s, what is her speed after she draws her arms

in?

SECTION - E

m1 m2 m3

T3 T1 T2

24 a) Derive an expression for the gravitational potential energy of an object placed at

certain distance from the center of earth. What is the significance of negative sign

in the expression?

b) A satellite orbits the earth at a height of 500 km from its surface. Compute its

I. Kinetic energy

II. Potential energy &

III. Total energy. (Given mass of the satellite = 300 kg, mass of earth = 6x10 24 kg

, radius of earth = 6.4x106 m and G = 6.67 x 10-11 Nm2/Kg2 )

Or

(A) Derive an expression for the acceleration due to gravity

(i) at a depth (d) from the surface of earth

(ii)at a height h from the surface of earth .

(B) Draw the graph showing the variation of g with

(i) Height above the surface of earth.

(ii) Depth below the earth's surface.

25 What do you mean by banking of road? Derive expression for maximum and minimum velocity

of a car on banked circular road.

Or

a) Define impulse.

b) State and prove impulse momentum theorem.

c) A bullet of mass 10 g moving with a velocity 20 m/s strikes and comes to rest inside

a wall

Find the impulse imparted to the wall by the bullet.

26 Prove the following

(a)For two angles of projection and 90- with same velocity u,

(i)range is same

(ii)heights are in the ratio of tan2 :1

(b) if the range and maximum height are equal , the angle of projection is tan-1

(4)

Or

A projectile is fired at an angle q with horizontal

a) Show that its trajectories are parabola.

b) Obtain expression for

i. Height attained.

ii. Time of flight.

iii. Horizontal range.

Model Paper-III

Kendriya Vidyalaya Sangathan

Half Yearly Examination Class-XI Physics (Theory)


Blue Print

S.No. Chapter/Unit

VSA


1 Mark 2 Marks

3 Marks

4 Marks

5 Marks


2 1 7




1 2 2 11


Body

1 3 10

6 Gravitation 1 1 1 1 11

7 Total 5(5) 5(10) 12(36) 1(4) 3(15) 26(70)

Model Paper-III

Kendriya Vidyalaya Sangathan Half Yearly Examination Class XI

PHYSICS (Theory)

Time: 3 Hrs. MM: 70


xvii. All questions are compulsory.

xviii. There is no overall choice. However, an internal choice has been provided in one question of



xix. Questions number 1 to 5 are very short answer type questions, carrying one marks each.

xx. Questions number 6 to 10 are short answer type questions, carrying two marks each.

xxi. Questions 11 to 22 are also short answer type questions, carrying three marks each.

xxii. Question number 23 is value based question, carrying four marks.

xxiii. Questions 24 to 26 are long answer type questions, carrying five marks each.

xxiv. Use of calculators is not permitted. However, you may use log tables, if necessary.

G = 6.67 X 10-11

Nm2/kg


24kg


SECTION - A

1

A car starts accelerating from rest for some time, maintains the velocity for some time and

then comes to rest with uniform deceleration. Draw the v-t graph?

2 Action and reaction are equal and opposite. Why do they not balance each other?

3 What is the work done earth gravitational force in keeping the moon in its orbit?

4 What is the angular velocity of hour hand of clock?

5 What is the reason for absence of atmosphere in some planets?

SECTION

6 The length and breadth of rectangle are (5.7±0.1) cm and (3.4±0.4)cm, Calculate area of

rectangle with error limits?

7 What is the difference between head on collision and glancing collision? Define coefficient

restitution.

8 Derive the expression for the variation of acceleration due to gravity ‘g’ with altitude ‘h’

OR

Derive the expression for the variation of acceleration due to gravity ‘g’ with depth ‘d’

9 State the principle of homogeneity of dimensions. Check the correctness of equation F=

mv2/r where symbols have usual meaning.

10 Define the kinetic energy. Prove that kinetic energy associated with mass m moving with

velocity v is ½ mv2.

11 A mass m moving with speed u collides with similar body of mass m at rest, elastically and

obliquely .prove that they will moves mutually perpendicular to each other.

12 Time of oscillation of a drop of liquid under surface tension depends upon the density

radius ‘r ‘and surface tension ‘T’. Prove dimensionally that t = K ( r3/T)

1/2

13 State theorem of perpendicular axis. Moment of inertia of disc about an axis passing through

its center and perpendicular to its plane is ½ MR2.find it’s moment of inertia about its

diameter.

14 A body starts from rest and accelerates uniformly .find the ratio of displacement in (i) one,

two & three seconds (ii) first, second & third second.

15 Derive an expression for the orbital velocity revolving in the orbit near the earth surface.

How is it related to escape velocity?

16 To a man going east in a car with a velocity of 40km/h, a train appears to move towards

north with a velocity of 40√3km/h. What is the actual velocity and direction of motion of the

train?

17 Define center of mass. Deduce expression for the center of mass of a two particle

system.

18 (i) Show that newton’s 2nd

law of motion is the real law of motion.

(ii) Which is easier, to pull or to push a lawn roller.

19 Two masses of m1 and m2 are connected with string with frictionless pulley. Find the

acceleration of system and tension in the string.

20 An elastic spring of spring constant k is compressed by an amount x. show that it potential

energy is ½ kx2.

Or

A body of mass 10 Kg is hung by a spring balance in a lift. What would be the reading of the

balance when (i) the lift is ascending with an acceleration of 2 ms-2

(ii) descending with the

same acceleration (iii) descending with a constant velocity of 2 ms-1

.(Take g=10ms-2

)

21 A particle of mass 0.5 kg travels in a straight line with velocity v = ax3/2

, where a = 5m/s2.

What is the work done by the net force during its displacement from x = 0 to x = 2m?

22 Obtain an expression for the minimum velocity of a body at the lowest point for looping a

vertical circle.

23 Mr. Ramesh always goes to office at CST by train. One day he saw a boy was doing stunts at

the door and there was no crowd that day. He refused the boy to doing all that. At CST that

boy tried to get down before the train stopped and suddenly the boy fell down. Mr. Ramesh

carried that boy the hospital and till the complete treatment he was there with him and went

to office.

a. Write the qualities of Mr. Ramesh.

b. Why was the boy fell down? Give the correct reason.

24 a) What is meant by gravitational potential? Write its expression at the surface of

the earth, assuming the earth to be sphere of radius (R) and mass (M) supposed

to be concentrated at its center

b) State Kepler’s laws of planetary motion.

Or

Define escape velocity. Derive expression for the same The escape velocity of a

projectile on the surface of earth is 11.2 km/s. If a body is projected thrice this

speed, find the speed of the body far away from the surface of earth . (Ignore

other planets)

25 Give reason for the following

i) An athlete runs a certain distance before taking a long jump

ii) A cricket player lowers his hands while catching a ball

iii) Shock absorbers are provided in scooters

iv) A horse can not pull a cart and run in empty space

v) Passengers are thrown forward from their seats when a speeding bus suddenly

stops

or

a) state the laws of limiting friction .

b) State two advantages and two disadvantages of friction.

c) Why are ball bearing are used in machinery

26

A boat is moving with a velocity )ˆ4ˆ3( ji with respect to the ground. The water in the

river is moving with a velocity )ˆ5ˆ2( ji with respect to ground. What is the relative velocity

of boat with respect to water?

OR

a) What do you mean by centripetal force? Derive an expression for the

centripetal force.

b) Establish a relation between liner velocity and angular velocity in a uniform

circular motion.

MODEL PAPER- 4




Blue Print

S. No.

Chapter Unit VSA SA I SA II VBQ LSA Total

1 Marks

2 Marks

3 Marks

4 Marks

5 Marks

1

Physical World and

Measurement 1 2 08


3 Laws of Motion

2 1 1 15

4 Work Energy and Power 1 1 1 1 11

5

Motion of System of

Particles and Rigid Body 1 2 2

11

6 Gravitation 1 3 10

Total 5 (5) 5 (10) 12 (36) 1 (4) 5 (3) 26 (70)

MODEL PAPER -IV

KENDRIYA VIDAYLAYA SANGATHAN

HALF YEARLY EXAM

PHYSICS (Theory)

Time allowed: 3 hours Maximum Marks: 70

Roll No.

General Instructions:

(i) All questions are compulsory. There are 26 questions in all.

(ii) This question paper has five sections : Section A, Section B, Section C, Section

D and Section E.

(iii) Section A contains five questions of one mark each, Section B contains five

questions of two marks each, Section C contains twelve questions of three

marks each, Section D contains one value based question of four marks and

Section E contains three questions of five marks each.

(iv) There is no overall choice. However, an internal choice has been provided in one

question of two marks, one question of three marks and all the three questions of

five marks weightage. You have to attempt only one of the choices in such

questions.

(v) You may use the following values of physical constants wherever necessary

SECTION - A

1 Two balls of different masses are thrown vertically upward with same initial velocity. Heights

attained by them are h1 and h2 respectively what h1/h2 is.

1

2 Why do we prefer to use long arm wrench. 1

3 An object is moving in a circular path with constant speed .state whether motion is uniform

motion or accelerated motion

1

4 How will momentum of a body will change if kinetic energy is doubled keeping mass of the body

remain same?

1

5 If earth were made of lead of relative density 1.3, other parameters remain constant, what would

be the value of g on the surface of earth.

SECTION -B

1

6 When the angle between two vectors of equal magnitudes is 2π/3, prove that the magnitude of the

resultant is equal to either.

2

7 The moment of inertia of two bodies A and B are IA and IB with IA > IB . If they have identical

angular momenta, which one has greater kinetic energy of rotation?

or

How is angular momentum of a particle in two dimensional motion related to the areal velocity of

the position vector of the particle?

2

8 A body of moment of inertia (I) starting from rest acquires angular velocity '' in a time ’t’

Find the torque acting on the body .

2

9 (i) Can a quantity have units but still be dimensionless? (ii) Can a quantity have dimensions but

still have no units? Justify your answer.

2

10 Prove work-energy theorem.

SECTION - C

2

11 Explain clearly the meaning of banking of tracks. Give the expression for optimum speed of

car for negotiating a banked curve for least wear and tear

3

12 Equal amounts of torques are applied to a hollow sphere and solid sphere of same mass and

radius . Both are free to rotate about an axis passing through its centre. Which of the two will

acquire greater angular speed?

3

13 The position of a particle is given by r

3 t i + 2 t2 j + 5 k where t is in seconds and the

coefficients have the proper units for r

to be in meters. (a) Find v

(t) and a

(t) of the particle. (b)

Find the magnitude and direction of v

(t) at t = 1 sec

3

14 A lift of mass 500 kg is hung by a wire. Calculate the tension in the wire when the lift is

(a) at rest, (b) moving upwards with constant velocity of 3m/s, (c) moving upwards with an

acceleration of 2m/s2. (Take g = 10m/s

2).

3

OR

A body of mass 10 Kg is hung by a spring balance in a lift. What would be the reading of the

balance when (i) the lift is ascending with an acceleration of 2 ms-2

(ii) descending with the same

acceleration (iii) descending with a constant velocity of 2 ms-1

.(Take g=10ms-2

)

15 State the number of significant figures in the following :

(a) 0.007 m2 (b) 2.64 × 10

24 kg (c) 0.2370 g cm

–3 (d) 6.320 J (e) 6.032 N m

–2 (f) 0.0006032

m.

3

16 Write expression for the acceleration due to gravity. If the radius of earth shrinks by 2%, mass

remaining the same, then how would the acceleration due to gravity changes.

3

17 The mass and diameter of a planet are twice those of earth. What will be time period of the

pendulum on this planet, which is a second’s pendulum on the earth?.

3

18 Two artificial satellites, one twice as heavier as the other has the same orbital radius. Which one

has more orbital speed? Give reason for your answer

3

19 Draw velocity-time graph for motion (a) along positive x-axis with acceleration in same

direction, (b) along positive x-axis with acceleration in opposite direction and (c) along negative

x-axis with acceleration in same direction.

3

20 What do you mean by the moment of inertia .Establish the relation between torque and moment

of inertia of a rigid body?

3

21 A gardener moves a lawn roller through a distance of 50m with a force of 100 N. If the force is

acting at an angle of 600 to the direction of motion, find the work done.

3

22 In an experiment the value of refractive index of a glass was found to be 1.54, 1.53, 1.44, 1.54,

1.56 and 1.47 in successive measurements. Calculate (i) value of refractive index of glass (ii)

absolute error in each measurement. (iii) Mean absolute error (iv) relative error. Also express the

result in terms of absolute error and percentage error.

SECTION - D

3

23 Suresh noticed a big Granite Rock in his locality. He thought that if they worked upon it they

could earn money. He took permission from the Government, completed all the formalities .He

broke the Rock using a bomb. The rock was made into slices .They established a Granite

industry. Many of the people in the surroundings started to earn and live comfortably.

Answer these questions:-

a) What values of Suresh impress you?

b) A bomb is thrown in a horizontal direction with a velocity of 50 m/s. It explodes into two

parts of masses 6 Kg and 3 Kg. The heavier fragment continues to move in the horizontal

4

direction with a velocity of 80 m/s Calculate the velocity of the lighter fragment. Give the

statement of the law applied in this case

24 a) What are the conservative and non-conservative forces? Give one example of each

b) A body of mass M is sliding on an inclined plane making an angle with the

horizontal. If is the coefficient of friction between the mass and the surface ,

represent the different forces acting on the body when the body is in motion . Find

the acceleration of body.

Or

a) In order to walk, why do we push our foot against the ground?

b) A helicopter of mass 1000 kg rises with a vertical acceleration of 15 m/s2 . The crew and

the passengers weigh 300 kg. Give the magnitude and direction of

i) Force on the floor by the crew and the passengers

ii) Action of the rotor of the helicopter on surrounding air

iii) Force on the helicopter due to surrounding air [ g = 10 m/s2]

5

25 a) State the parallelogram law of vector addition. Using the concept of parallelogram law of

vector addition , Find the magnitude and direction of | BA

|.

b) At what angle two forces (P + Q) and (P - Q) act so that resultant is

(i) √ (3P2 + Q

2) and (ii) √2(P

2 + Q

2).

OR

A particle is projected with a velocity u at angle to the horizontal in a vertical plane . Derive

expressions for (a) maximum height ; (b) time of flight ; and (c) horizontal range .

A cricketer can throw a ball to a maximum horizontal distance of 100 m . How high above the

ground can he throw the same ball?

5

26 Obtain an expression for the minimum velocity, tension in the string when the body is at the

lowest point & highest point for looping a vertical circle.

A bucket of water is tied at the end of a 4.5 m long rope and is rotated about the other end in a

vertical circle. Find the minimum velocity at the highest and lowest points such that water in the

bucket does not spill.

OR

What do you mean by elastic and inelastic collision? give one example of each.

I. A lighter body collides with much more massive body elastically which is at rest, prove

that the direction of the lighter body is reversed and massive body remains at rest.

5

II. Show that in a head on collision between two balls of equal masses moving along a straight

line, the balls simply exchange their velocities.

MODEL PAPER -V




Blue Print

S.No. Chapter/Unit

VSA


1 Mark 2 Marks

3 Marks 4 Marks

5 Marks


2 1 7




1 1 2 9


Body

1 3 1 15

6 Gravitation 1 2 1 11

7 Total 5(5) 5(2) 12(36) 1(4) 3(15) 26(70)

MODEL PAPER -V

Kendriya Vidyalaya Sangthan

Half yearly examination

XI – PHYSICS (THEORY)

Time: Three Hours Max. Marks: 70

General Instructions -

(a) All questions are compulsory.

(b) There are 30 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 18 carry two

marks each, questions 19 to 27 carry three marks each and questions 28 to 30 carry five marks each.

(c) There is no overall choice. However, an internal choice has been provided in one question of two

marks, one question of three marks and all three questions of five marks each. You have to attempt

only one of the given choices in such questions.

(d) Use of calculators is not permitted.

SECTION A

1. What does the slope of velocity-time graph indicate?

2. An object is thrown with a velocity of 12 m/s at an angle 300 above the ground. What is its velocity at

the topmost point?

3. State work energy theorem and write its mathematical form

4. If two particles of masses m1 and m2 move with velocities v1 and v2 towards each other on a smooth

horizontal plane, what is the velocity of their centre of mass?

5. How is the gravitational force between two point masses affected when they are dipped in water

keeping the separation between them the same?

SECTION B

6. Two straight lines drawn on the same x-t curve make angles 300 and 600 with time axis. Which line

represents greater velocity? What is the ratio of the two velocities?

7. A physical quantity X is related to four measurable quantities a, b, c and d as follows: X = a2

b3 c5/2 d–2.

The percentage error in the measurement of a, b, c and d are 1%, 2%, 3% and 4%, respectively. What

is the percentage error in quantity X?

8. If E,M,J and G respectively denote energy, mass, angular momentum and gravitational constant, Calculate

the dimensions of EJ2 /M5G2

9. Two bodies A and B having masses mA and mB respectively have equal kinetic energies. If PA and PB are

their respective momenta, then prove that the ratio of momenta is equal to the square root of ratio of

respective masses.

10. Is larger surface area break on a bicycle wheel more effective than small surface area brake? Explain?

SECTION C

11. (a) State the principal of conservation of angular momentum.

(b) A child stands at the centre of a turntable with his two arms outstretched. The turntable is set

rotating with an angular speed of 40 rev/min. How much is the angular speed of the child if he folds

his hands back and thereby reduces his moment of inertia to 2/5 times the initial value? Assume that

the turntable rotates without friction.

12. There are four forces acting at a point P produced by strings as shown in Figure, which is at rest. Find

the forces F1 and F2 .

13. If kinetic energy of a body is increased by 300%, by what percentage will linear momentum of the

body increase?

14. A cord of negligible mass is wound round the rim of a fly wheel of mass 20 kg and radius 20 cm. A

steady pull of 25 N is applied on the cord as shown in Figure. The flywheel is mounted on a horizontal

axle with frictionless bearings. Calculate the angular acceleration of the wheel.

15. The frequency of vibration (υ) of a string may depend upon length (l) of the string, tension (T) in the

string and mass per unit length (m) of the string. Using the method of dimensions, derive the formula

for υ.

16. A particle starts from origin at t = 0 with a velocity 5.0 î m/s and moves in x-y plane under action of a

force which produces a constant acceleration of (3.0 î + 2.0j) m/s2. (a) What is the y-coordinate of the

particle at the instant its x-coordinate is 84 m? (b) What is the speed of the particle at this time?

17. (a) Why do not the action and reaction cancel in Newton’s III law of motion?

(b) What is meant by an impulsive force? State impulse - momentum relationship.

18. Establish the relation between torque and angular acceleration. Hence define moment of inertia.

OR

F = 25N

R

Define angular momentum. Prove that the time rate of change of the angular momentum of a particle is

equal to the torque acting on it.

19. Draw position –time graphs of two objects , A and B moving along straight line, when their relative

velocity is (i) zero (ii)positive (iii) negative.

20. Define work. A body constrained to move along the Z – Axis of a coordinate system is subjected to a

constant force F given by = - i + 2j + 3k N where i, j, and k are the unit vectors along the x, y and z axis of

the system respectively. What is the work done by this force in moving the body a distance of 4 m along

the Z axis?

21. What do you understand by gravitational field, Intensity of gravitational field. Prove that gravitational

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

22. State universal law of gravitation. What is the significance of this law. Find the expression for acceleration

due to gravity.

SECTION D

23. Adarsh a student of class XI has found the factors on which the time period of oscillation of a pendulum

depends and arrived at the expression T = (constant) X (l/g)⅟2 . He wants to know how the length of the

pendulum gets affected on the surface of the moon for the same pendulum and arrived at the conclusion

that it is l/6.

(a) What values does Adarsh possesses?.

(b)The length of a seconds’ pendulum on the surface of the earth is 1m what will be the length on the

surface of the moon?

SECTION E

24. State theorem of perpendicular and parallel axis.

(a) Find the moment of inertia of a sphere about a tangent to the sphere, given the moment of inertia

of the sphere about any of its diameters to be 2

5

2MR , where M is the mass of the sphere and R is the

radius of the sphere.

(b) Given the moment of inertia of a disc of mass M and radius R about any of its diameters to be

2

4

1MR , find its moment of inertia about an axis normal to the disc and passing through a point on its

edge.

Or

Define centre of mass of a system of particles. Calculate the centre of mass of a system of two particles. In

the HCl molecule, the separation between the nuclei of the two atoms is about 1.27 A0. Find the

approximate location of the centre of mass of the molecule. Given: chlorine atom is about 35.5 times a

massive as a hydrogen atom and nearly all the mass of an atom is concentrated in its nucleus

25. State triangle law of vector addition. . Using it finds the magnitude and direction of the resultant of

two vectors and which are inclined at an angle θ. In what conditions the resultant of two vectors

is maximum and minimum?

OR

What do you mean by projectile motion? A point object is projected at an angle θ with the horizontal

with velocity from the ground and the object strikes the ground on the same level as that of

projection after some time. Prove that -

(i) The trajectory of the projectile is parabolic.

(ii) If the horizontal range and maximum height are equal, the angle of projection is .

26. (a) What is the necessity of banking of roads at turns? Obtain an expression for maximum speed with

which a vehicle can safely negotiate a curved road banked at an angle θ with frictional coefficient µ.

(b) Determine the angle of banking so as to minimize the wear and tear of tyres of a vehicle negotiating

a banked curve road.

OR

A rectangular box lies on a rough inclined surface. The co-efficient of friction between the surface and

the box is μ. Let the mass of the box be m.

(a) Determine the angle of inclination θ of the plane to the horizontal at which the box just start to

slide down the plane?

(b) What is the force acting on the box down the plane, if the angle of inclination of the plane is

increased to α > θ?

(c) What is the force needed to be applied upwards along the plane to make the box either remain

stationary or just move up with uniform speed?

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