ANNUAL REVISION WORKSHEET

Class XI MAX MARKS: 70

SUBJECT: PHYSICS (042) DURATION: 3Hr

General Instructions:
(1) There are 33 questions in all. All questions are compulsory.
(2) This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
(3) All the sections are compulsory.
(4) Section A contains sixteen questions, twelve MCQ and four Assertion & Reasoning based of 1 mark each,
Section B contains five questions of two marks each, Section C contains seven questions of three marks each,
Section D contains two case study-based questions of four marks each and Section E contains three long answer
questions of five marks each.

SECTION-A
S MARKS
NO
1. If the displacement of an object is zero, then what can we say about 1
its distance covered?
(a) It is negative (b) It is must be zero
(c) It cannot be zero (d) It may or may not be zero
2. A rocket with a lift-off mass 2.5x104 kg is blasted upwards with an 1
initial acceleration of 10 m/s2. Then the initial thrust of the blast is
(a) 2.5 x105 N (b) 5 x105 N (c) 14 x105 N (d) 1.75 x105N
3. In solids interatomic forces are 1
(a) totally repulsive (b) totally attractive
(c) partially repulsive (d) partially attractive
4. Radius of gyration of a body depends upon 1
(a) Axis of rotation (b) translational motion
(c) shape of the body (d) area of the body
5. A system consists of particles each of mass m and located at (1,1), 1
(2,2), (3,3). The coordinates of the centre of mass
(a) (6,6) (b) (3,3) (c) (2,2) (d) (1,1)
A wire fixed at the upper end stretches by length (L) by applying a 1
6. force (F). The work done in stretching is
(a) F/2L (b) FL (c) 2FL (d) FL/2
7. A closed compartment containing gas is moving with some 1
acceleration in horizontal direction. Neglect effect of gravity. Then
the pressure in the compartment is
(a) Same everywhere (b) lower in the front side
(c) lower in the rear side (d) lower in the upper side
 8. A constant volume air thermometer works on 1
(a) Archimedes’ principle (b) Boyle's law
(c) Pascal's law (d) Gay Lussac's law.

9. An electric heater supplies heat to a system at a rate of 100W. If 1

system performs work at a rate of 75 joules per second. At what
rate is the internal energy increasing?
(a) 25 W (b) 50 W (c) 75 W (d) 100 W
10. A gas mixture consists of 2 moles of oxygen and 4 moles of Argon at 1
temperature T. Neglecting all vibrational moles, the total internal
energy of the system is
(a) 4RT (b) 9 RT (c) 11RT (d) 15 RT
11 . Which of the following is not essential for S.H.M.? 1
(a) Gravity (b) Restoring force (c) Inertia (d) Material medium
12. Whenever a wave enters from one medium to the another, its 1
(a) velocity constant (b) frequency constant
(c) Wavelength constant (d) time period constant.
For Questions 13 to 16, two statements are given –one labeled
Assertion (A) and other labeled Reason (R). Select the correct
answer to these questions from the options as given below.
a) If both Assertion and Reason are true and Reason is correct
explanation of Assertion.
b) If both Assertion and Reason are true but Reason is not the
correct explanation of Assertion.
c) If Assertion is true but Reason is false.
d) If both Assertion and Reason are false.
13. Assertion: On a rainy day, it is difficult to drive a car or bus at 1
high speed.
Reason: The value of coefficient of friction is lowered due to wetting
of the surface.
14. Assertion: A particle strikes head-on with another stationary 1
particle such that the first particle comes to rest after collision. The
collision should necessarily be elastic.
Reason: In elastic collision, there is a loss of momentum of the
system of the Particles.
15. Assertion: If the ice on the polar caps of the earth melts, then 1
length of day will Increase.
Reason: Moment of inertia of the earth increases, as ice on polar
caps melts
16. Assertion: Stress is the internal force per unit area of a body 1
Reason: Rubber is more elastic than steel
SECTION B
17. Why girders given I shaped 2
18. Derive equations of motion for uniformly accelerated motion from 2
velocity-time graph
19. What is Reynold’s number? What is its importance 2
20. In a heat engine, the temperature of the source and sink are 500K 2
and 375 K. if the engine consumes 25 x 10 5 J per cycle, find (i) the
efficiency of the engine (ii) work done per cycle
21. Define Hooke’s law. Give its units and dimensions. 2
(OR)
Derive gas laws from the kinetic theory of gases
SECTION C
22. Derive work done in adiabatic process 3
23. Show that the average KE of a gas molecule is directly proportional 3
to the temperature of the gas
24. Describe the stress-strain curve for a metallic wire with neat 3
diagram.
25 State & prove Bernoulli's principle for the flow of non-viscous fluids 1+2
with diagram
26. What should be the pressure inside a small air bubble of 0.1mm 3
radius situated just below the water surface? Surface tension of
water=7.2×10−2N/m and atmospheric pressure=1.013×10 5N/m2
27. Obtain an expression for the heat conducted and hence define
coefficient of thermal conductivity and give its units and
dimensions.
28 A brass wire1.8 m long at 270 C is held taut with little tension 3
between two rigid supports. If the wire is cooled to a temperature of
−390 C, what is the tension developed in the wire, if its diameter is
2.0 mm? Co-efficient of linear expansion of brass=2x10 -5 0 C-1,
Young's modulus of brass=0.91x10 11 Pa.
CASE BASED QUESTIONS: Read the following paragraph and
answer the questions that follow.
29. The first law of thermodynamics is the general law of conservation
of energy applied to any system in which energy transfer from or
to the surroundings (through heat and work) is taken into
account. It states that the energy supplied to the system goes in
partly to increase the internal energy of the system and the rest in
work on the environment. Mathematically, ΔQ =ΔU +ΔW where ΔQ
is the heat supplied to the system, ΔW is the work done by the
system and ΔU is the change in internal energy of the system. ΔQ
and ΔW depend on the path taken to go from initial to final states,
but the combination ΔQ –ΔW is path independent.
29. The first law of thermodynamics is concerned with the 1
1 conservation of
(a) number of molecules (b) number of moles
(c) energy (d) temperature
29. Which of the following is not a path function? 1
2 (a)ΔQ (b) ΔQ +ΔW (c) ΔW (d) ΔQ –ΔW
29. An electric heater supplies heat to a system at a rate of 120 W. If 1
3 system performs work at a rate of 80 J/ s, the rate of increase in
internal energy is
(a) 30 J/ s (b) 40 J/ s (c) 50 J /s (d) 60 J /s
29. What is the fundamental concept in thermodynamics that involves 1
4 two bodies in contact reaching a state with no net heat transfer
between them?
(a) Thermal equilibrium (b) Entropy (c) Conservation of energy
(d) Internal energy
30. Read the following paragraph and answer the questions that
follow.

Pressure of an Ideal Gas: According to kinetic theory of gases

pressure is given by P = 1/3 nmv 2Where, n is number of molecules
per unit volume, m is mass and v 2 is mean squared speed. Though
we choose the container to be a cube, the shape of the vessel really
is immaterial. The average kinetic energy of a molecule is
proportional to the absolute temperature of the gas, it is
independent of pressure, volume or the nature of the ideal gas. This
 is a fundamental result relating temperature, a macroscopic
measurable parameter of a gas (a thermodynamic variable as it is
called) to a molecular quantity, namely the average kinetic energy of
a molecule. The two domains are connected by the Boltzmann
constant and given by E = kb T. Where kb is Boltzmann constant, we
have seen that in thermal equilibrium at absolute temperature T,
for each translational mode of motion, the average energy is ½ k b T.
In general, we can say that number of degrees of freedom is equal to
the total number of coordinates required to specify the position of
the constituent particles of the system minus the number of
independent relations existing between the particles.
30. Boltzmann constant has value of 1
1 (a) 1.38 X 10-23joule per Kelvin (b)1.38 X 10 -28 joule per Kelvin.
(c) 1.38 X 10-30joule per Kelvin. (d) 1.38 X 10 30 joule per Kelvin

30. What is the value of degree of freedom for a mono atomic gas 1
2 (a)1 (b) 3 ( c) 5 (d) 7
30. The molecular velocities are almost equally distributed because gas 1
3 molecules are
(a)Isotopes (b) isobars (c ) isotropic (d)isomers
30. The relation between pressure and kinetic energy per unit volume is 1
4 (a)5/3 (b) 1/3 (c ) 7/3 (d) 2/3
SECTION E
31 Describe the operation of a Carnot’s engine. Calculate the efficiency 3+2
of Carnot’s engine and explain why the efficiency of an irreversible
engine is small
(OR)
(i) State and explain first law of thermodynamics with neat diagram.
(ii) Two moles of an ideal gas initially at 27 0 C and one atm pressure
are compressed isothermally and reversible till the final pressure of
the gas is 10 atm. Calculate Q

32 3+2
(i) Derive the expression for potential and kinetic energy of a particle
under SHM
(ii) A simple harmonic motion is represented by x=10 sin (20 t+0.5),
write down its amplitude, angular frequency, frequency and its time
period.
(OR)
(i) List the assumption of kinetic theory of a gas.
(ii) calculate r.m.s the velocity of hydrogen at N.T.P given the
density of hydrogen = 0.09kgm4
33 (i) Describe the various modes of vibrations of an open organ pipe 3+2
with neat diagram.
(ii) A tuning fork arrangement (pair) produces 4 beats/sec with one
fork of frequency 320 cps. A little wax is placed on the unknown
fork and it then produces 3 beats/sec. What is the frequency of the
unknown for k?
(OR)
(i) Define progressive wave? Establish the displacement relation for
harmonic wave travelling along the positive direction of x-axis.
(ii) Distinguish between progressive wave and standing wave.