# Class 11 Physics Sample Paper

Please refer to the Class 11 Physics Sample Paper for the current academic year given below. We have provided the latest CBSE Sample Papers for Term 1 and Term 2 for Physics Class 11. All guess sample papers have been prepared based on the latest blueprint and examination pattern for the current year. All sample papers for Physics Class 11 Term 1 and 2 have been given with solutions. Students can access the multiple guess papers given below. Practicing more Class 11 Physics Sample Papers will help you to get more marks in upcoming exams.

## CBSE Sample Papers for Class 11 Physics

Class 11 Physics Sample Paper Term 1 Set A

SECTION – A

1. If a gas having N molecule has k number of constraints, how many degrees of freedom does the gas possess?
Answer : Number of degrees of freedom f = 3 N – k.

2. Identical springs of steel and copper are equally stretched. On which, more work will have to be done?
Answer : Work done to stretch a spring is given by

OR
A spring is stretched by applying a load to its free end. What type of strain produced in the spring?
Answer : Longitudinal and Shearing Strain is produced in spring.

3. When we start filling an empty bucket with water, the pitch of sound produced goes on changing. Why?
Answer : A bucket may be regarded as a pipe closed at one end. It produces a note of frequency,
v = v/4L
where v is the velocity of sound in air and L is the length of air column, which is equal to depth of water level from the open end. As the bucket is filled with water, the value of L decreases. Consequently, the frequency and hence the pitch of the sound produced goes on changing.

4. Two particles execute S.H.M. of same amplitude and frequency along the same straight line. They pass one another when going in opposite directions, each time their displacement is half of their amplitude. Find the phase difference between them.

OR
Displacement versus time curve for a particle executing SHM is as shown in figure.

At what points the velocity of the particle is zero?
Answer : At point A, C and E, the velocity of the particle will be zero.

5. What is effect on the viscosity of a gas if the temperature is decreased?
Answer : If the temperature is decreased, there is a decrease in the viscosity.

statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false and R is also false

6. Assertion (A) : Water waves in a river are not polarized.
Reason (R) : Water waves are longitudinal as well as transverse in nature.

A

7. Assertion (A) : Water kept in an open vessel will quickly evaporate on the surface of the moon.
Reason (R) : The temperature at the surface of the moon is much higher than boiling point of water.

A

SECTION – B

Case Study Based Question :

8. The motion repeated in equal interval of time is called the periodic motion. The smallest interval of time after which the motion repeats itself is called its time period (T). The reciprocal of T gives the number of repetition occurs per unit time which is termed as frequency of periodic motion. The functions which are used to represent periodic
motion are called periodic functions i.e., f(t) = A cos ωt.
As the function will repeat itself after time period T therefore f(t) = f(t + T) = f(t + 2T) = …………………. where, {T = 2π/ω}
Periodic functions can also be expressed as a linear combination of sine and cosine function i.e.,
f(t) = A sinwt + B cos ωt. In periodic motion, displacement refers to change in physical property like amplitude of sound wave, changing electric and magnetic fields etc.

(i) On an average, a human heart is found to beat 72 times a minute. Its frequency and period are
(a) 1.2 Hz, 0.83 s
(b) 2.5 Hz, 1.2 s
(c) 2 Hz, 1.2 s
(d) 2.5 Hz, 0.83 s

A

(ii) The circular motion of a particle with constant speed is
(a) periodic but not SHM
(b) SHM but not periodic
(c) periodic and also SHM
(d) neither periodic nor SHM

A

(iii) Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half of the amplitude. The mean positions of the two particles lie on a straight line perpendicular to the paths of the two particles. The phase difference is
(a) π/6
(b) 0
(c) 2π/3
(d) π

C

(iv) Which of the following statements is correct?
(a) An oscillatory motion is necessarily periodic.
(b) A periodic motion is necessarily oscillatory.
(c) A simple harmonic motion is not necessarily periodic.
(d) A simple harmonic motion is necessarily oscillatory.

D

(v) Which of the following statements are correct.
(a) The displacement of a particle in SHM in one time period is equal to 4A, where A is the amplitude.
(b) A particle is moving in a circle with uniform speed. Its motion is simple harmonic.
(c) A particle is moving in a circle with uniform speed. Its motion is periodic.
(d) None of these

C

SECTION – C

9. Derive the P-V relation for a monatomic gas undergoing an adiabatic process.
Answer : From first law of thermodynamics,

OR
A gaseous mixture contain 32 g of helium and 32 g of oxygen, then calculate the ratio of CP/CV of the  mixture.

10. The length of a rubber cord is l1 m when the tension is 4 N and ∫2 m when the tension is 6 N. The length when the tension is 9 N, is
Answer : (a) : Let the original unstretched length be ∫.

11. Water on a clean glass plate spreads into a thin film but a small amount of water placed on a flat surface of wax forms into drops. Why?
Answer : The force of adhesion between the molecules of water and glass is more than the force of cohesion between the water molecules. Thus, when water is dropped on the glass plate, it spreads on it. On the other hand, the force of cohesion between water molecules is more than the force of adhesion between water and wax molecules. Thus, on account of this higher force of cohesion, water instead of spreading on wax forms into drops.
OR
Bernoulli’s theorem holds for incompressible, non-viscous fluids. How this relationship changed when the viscosity of fluid is not negligible?
Answer : The effect of viscosity, which is internal friction in case of fluids, is to dissipate mechanical energy of the fluid into heat. Thus, in case the viscosity of a fluid is not negligible, the quantity P + rgh + (1/2)pv2 goes on decreasing along the direction of flow of the fluid.

12. A gaseous mixture enclosed in a vessel consists of 1 g mole of a gas A {γ = 5/3} and some amount of gas B {γ = 7/5} at a temperature T. The gases A and B do not react with each other and are assumed to be ideal. Find number of gram moles of the gas B, if g for the gaseous mixture is {19/13}.

SECTION – D

13. A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram). The density of the oil is

14. An air bubble of diameter 2 mm rises steadily through a solution of density 1750 kg m–3 at the rate of 0.35 cm s–1. Calculate the coefficient of viscosity of the solution. The density of air is  negligible.

OR
Define the terms molecular range, sphere of influence and surface film.
Answer : Molecular range : It is the maximum distance upto which a molecule can exert some appreciable force of attraction on other molecules. It is of the order of 10–9 m in solids and liquids.
Sphere of influence : A sphere drawn around a molecule as centre and with a radius equal to the molecular range is called the sphere of influence of the molecule. The molecule at the centre attracts all the molecules lying in its sphere of influence.
While studying the behaviour of a molecule under the influence of cohesive forces, we need to consider only the molecules lying in its sphere of influence.
Surface film : A thin film of liquid near its surface having thickness equal to the molecular range for that liquid is called surface film.

SECTION – E

15. Let n moles of an ideal gas in a cylinder of unit cross section with a piston attached as shown in figure. A spring of spring constant K is attached (unstretched length L) to the piston and to the bottom of the cylinder. Initially the spring is unstretched and the gas is in equilibrium. A certain amount of heat Q is supplied to the gas causing an increase of volume from Vo to V

(a) What is the initial pressure of the system?
(b) What is the final pressure of the system?
(c) Using the first law of thermodynamics, write down a relation between Q, Pa, V, Vo and k.
Answer : Given, cross-sectional area of the piston

OR
(a) One mole of an ideal gas undergoes a cyclic process ABCD A as shown in the P-V diagram,

What is the net work done in the process ? (1 atm = 106 dyne cm–2)
(b) A sample of an ideal monatomic gas is taken round the cycle ABCA as shown in figure. What is the work done, during the cycle ?