### Sample questions paper class11 cbse physics

__CBSE SAMPLE QUESTIONS PAPER- CLASS 11__**Grade : XI Subject: PHYSICS Marks: 70**

**Time : 3hrs**

*General Instructions*:*a) All the questions are compulsory.*

*b) There are 37 questions.*

*d) Section-A contains 20 one mark questions.(MCQs, fill in the blanks and definitions)*

*e) Section-B contains 7 two mark questions with choice questions.*

*f) Section-C contains 7 three mark questions with choice questions.*

*g) Section –D contains 3 five mark questions with internal choice.*

__SECTION – A__
1.
Special theory of relativity explained by

a)
Thomas Alva Edison b)
Ampere

c) Albert Einstein d) C V Raman

2.
Among the
given following units which one is the longest unit of length?

a)
Angstrom b)
Fermi

c) Barn d) Parsec

3. Dimensional formula of universal
gravitational constant______________

a) MLT

^{-1}b) ML^{-1}T^{-2}
c) M

^{-1}LT^{-2}d) None of the above
4. What is the value of dot product between i and j ____________

5. Which of the following statement is true regarding the Newton’s third law of motion?

a) To every action there is always an equal and opposite
reaction

b) Force proportional to acceleration of the body

c) Acceleration of the body proportional to force

d) Unless an external force acting on the body, the body will continue in the state of rest or of uniform motion

6. Units of moment

**a) meter b) kg c) kg meter d) newton meter**

7. What happens when angular velocity of
the Earth increases?

a) Acceleration due to gravity
decreases at the equator

b) Acceleration due to gravity
increases at the equator

c) moment of inertia of the earth
increases

d) None of the above

8. Elasticity of a material can be
altered by

a) hammering b) annealing

c) adding impurities d)
all of the above

9. The
amount of heat that a body can absorb by radiation___________

a) depends on colour of body only

b) depends on temperature of body only

c) depends on colour and temperature
of body only

d) depends on density of body

10. Specific heat value in isothermal process ________

a) one b) constant

c) infinity d) always more than 1

11. Dimensional formula of surface tension is
_______________

12. Two masses of 1g and 4g are moving with
equal kinetic energy. The ratio of the magnitudes of

their velocity is _____________

13. Orbital velocity of satellite on the
surface of earth is approximately _______________ km/s

*Or*
1 atmosphere = ________________________ N/m

^{2}
14. The efficiency of Carnot engine working
between sink and source of temperatures 100k and 400k is ___________________

15. A simple harmonic motion is represented by y = Sin (628 t) metre. Its frequency
of the wave is _________________ hz

16. What is the relation between initial
velocity of the projectile and time of flight?

17. Define Rigidity’s modulus of elasticity.

18. What happens to frequency of the pendulum
when it taken to the top of a mountain.

*Or*
A force of 5N acts on a body for 2
milli sec. If the mass of the body is 5g, calculate the change in momentum.

19. Define first law of thermodynamics.

20. Write the differences between longitudinal
and transverse waves.

__SECTION - B__
21. What is the moment of inertia along a
tangent of sphere of mass m and radius R. Give the factors affecting the moment
of inertia of the body.

22. Two stones are falling at a place from heights
in the ratio 2.3 what is the ratio of their velocities

on reaching the ground.

23. The angular velocity of a wheel increases
from 120 to 480 rpm in 10sec. The number of revolutions made during this time
is?

*Or*
Derive the expression for Kinetic
energy of a body vibrating in SHM.

24. The average depth
of Indian Ocean is about 3000 m. Calculate the fractional compression, of water
at the bottom of the ocean. (given bulk modulus k of water is 2.2 x 109 Nm-2 & acceleration due to gravity g
=10 ms-2)

*Or*
Derive an expression work done in
isothermal process. And Discuss the internal energy change in isothermal process and adiabatic
process .

25. State and explain Kepler’s laws of
planetary motion. And explain why hydrogen is in abundance around the sun but
not around earth?

26. What A liquid takes 3 minutes to cool from
80

^{0}C to 60^{0}C. How much time will it take to cool from 60^{0}C to 40^{0}C? The temperature of the surroundings is 20^{0}C.
27. Define

a) Mean free path

b) Explain the effect of pressure of
the gas and diameter of the molecule on mean free path.

__SECTION - C__
28. 28. a)
A lift is accelerated downward. Will the weight of the person inside the
lift increase, decrease or remain the same?

b)
If the lift is going up with uniform speed,
then?

c) Explain about variation of g with height and
depth..

29. Derive

a) v = u + at b) define nonuniform velocity and uniform acceleration

30. State and
prove perpendicular axis theorem. What is moment of inertia for a circular disc
of radius R and mass M along tangent perpendicular to its diameter?

31. Describe the behaviour of a wire under
gradually increasing load.

*Or*
Explain the experimental determination of Young's modulus with necessary diagram.

32. a) Define inertia and explain different
types of inertia with examples.

b) If a table is to be taken from one corners of a room
to another corner which is better pulling or pushing? Explain.

33. a) State and prove work-Energy theorem. b) Give the units and dimensions for co-efficient
of restitution.

34. A spring mass system is executing simple harmonic motion as
shown below.

a.
Write a general equation for the displacement, as a
function of time.

b.
Using the above equation, find the equations for
velocity and acceleration.

c.Plot
graphs showing the variations of displacement ‘

*x’*, velocity ‘*v’*and acceleration ‘*a*’ as a function of time.

__SECTION - D__
35.

**a.**Explain about Young’s modulus and give the experimental details to measure the Young’s modulus of a material wire.
b. If an iron wire is stretched by 1%, what is
the strain on the wire?

*Or***c.**What is Doppler Effect? Obtain an expression for the apparent frequency heard by the

observer in case of source is
moving towards the observer and observer at rest.

d.
Discuss about harmonics formed in a closed pipe.

36.

**a.**Define adiabatic process. Obtain the expression for work done in an adiabatic process.
b. Why a heat engine with 100% efficiency can never be realized in practice?
Explain with the help of Carnot’s engine efficiency expression.

*Or***c.**State Bernoulli’s theorem for an incompressible fluid.

**d.**With a neat sketch, explain how one can measure the flow speed of incompressible fluid. Give an equation for flow speed.

37.

**a.**Prove that the path of a projectile is a parabola.**b.**Give the properties of dot product and give one example.

*Or***a.**The diagrams below show two balls A and B on a horizontal surface. Initially ball B is at rest and ball A is moving with speed

*u*along a line joining the centers of the balls.

Using the law of conservation of linear momentum and law of conservation of kinetic energy, obtain the equations for velocity of ball A and ball B. | |||||

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