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Board
of Intermediate & Secondary Education
Gujranwala
Annual Examination 2025
Physics
Class XII (Second Year) — Chapters 5 & 6
Time Allowed: 3 Hours Paper Code: PHY-XII-2025 Total
Marks: 68
Name:
Roll No:
Centre:
General
Instructions for Candidates
|
Section |
Type |
Total
Questions |
To
Attempt |
Marks
Each |
Total
Marks |
|
A |
Multiple
Choice Questions |
12 |
12 |
1 |
12 |
|
B |
Short
Answer Questions (3 Parts) |
6
× 3 = 18 |
5
× 3 = 15 |
2 |
30 |
|
C |
Long
/ Extensive Questions (a + b) |
5 |
3 |
5
+ 3 = 8 |
24 |
|
Grand
Total: |
66 |
||||
Section
A — Multiple Choice Questions
All questions are compulsory. Tick (✓) the correct option. 12 × 1 = 12 Marks
Tick (✓) the correct answer.
1. The region of stress-strain curve
which obeys Hooke's law is:
(a) proportional limit
(b) elastic region
(c) plastic region
(d) yield limit
2. Which
of the following is more elastic?
(a) Rubber
(b) Wood
(c) Sponge
(d) Steel
3. Which
of the following is polymer acid?
(a) Wool
(b) Glass
(c) Sodium chloride
(d) Copper
4. The
effect of decrease of pressure with the increase in speed of a fluid in
horizontal pipe is:
(a) Torricelli's effect
(b) Bernoulli's effect
(c) Venturi's
effect
(d) Doppler's effect
5. The
pressure will be low when speed of a fluid is:
(a) zero
(b) high
(c) low
(d) constant
6. The
principle of floatation is a direct application of:
(a) Pascal's law
(b) Bernoulli's principle
(c) Archimedes' principle
(d) Newton's third law
7. In an
isothermal change, internal energy:
(a) decreases
(b) increases
(c) remains the same
(d) becomes zero
8. First
law of thermodynamics is based upon law of conservation of:
(a) mass
(b) energy
(c) momentum
(d) charge
9. When
the system is expanded by adding heat energy, the work done will be:
(a) positive and on the system
(b) negative and on the system
(c) positive and by the system
(d) negative and by the system
10. What
happens to internal energy of an object when its temperature increases?
(a) decreases
(b) remains constant
(c) increases
(d) fluctuates
11. In
medical field, a ventura mask, used to deliver a
known oxygen concentration to patients operates is based on:
(a) Newton's third law
(b) Archimedes' principle
(c) Pascal's law
(d) Bernoulli's principle
12. Which
of the following is a defining characteristic of a superfluid?
(a) Zero viscosity
(b) Infinite density
(c) Zero temperature
(d) Infinite thermal
conductivity
Section
B — Short Answer Questions
Part I — Solids and Fluid Dynamics (Chapter 5)
Attempt any FIVE (5) questions from this part. 5 × 2 = 10 Marks
Q.1 What is meant by (i) cohesive
force (ii) viscosity?
Q.2 Differentiate between streamline and turbulent flow of a
fluid.
Q.3 How does pressure change with depth in fluids?
Q.4 How is the flow rate related to the cross-sectional area
and velocity of the fluid?
Q.5 How does an object float or sink according to
Archimedes' Principle?
Q.6 Differentiate between stress, strain and Young's
modulus. Write down their SI units.
Part
II — Heat and Thermodynamics (Chapter 6)
Attempt any FIVE (5) questions from this part. 5 × 2 = 10 Marks
Q.7 What is meant by internal energy? How is it related to
temperature of an ideal gas?
Q.8 State 2nd law of thermodynamics in two different forms.
Q.9 Is it possible to construct a heat engine of 100%
efficiency? Explain.
Q.10 Differentiate between reversible and irreversible
processes.
Q.11 Why is adiabat steeper than
isotherm? Explain.
Q.12 What is meant by thermal equilibrium? Explain briefly.
Part
III — Comprehensive / Conceptual Questions
Attempt any FIVE (5) questions from this part. 5 × 2 = 10 Marks
Q.13 The ratio stress/strain remains constant for small
deformation. What will be the effect on this ratio when the deformation made is
very large?
Q.14 When pure water falls on a flat glass plate, it spreads
on the plate while the mercury, which falls on the same plate gets converted
into small globules. Why?
Q.15 According to Bernoulli's theorem, the pressure of a
fluid should remain uniform in a pipe of uniform radius. But actually, it goes
on decreasing. Why is it so?
Q.16 Why wings of an aeroplane are
rounded outward while flattened inward?
Q.17 Explain how thermodynamics applies to biological
systems, such as human body.
Q.18 A refrigerator transforms heat from cold to hot body.
Does this violate the second law of thermodynamics? Justify your answer.
Section
C — Extensive / Long Questions
Attempt any THREE (3) out of five. Each has part (a)
Numerical & part (b) Descriptive. 3 × 8 = 24 Marks
Note: Part (a) is
Numerical [5 Marks]
| Part (b) is Descriptive/Theoretical [3
Marks]
Q.1
(a) A steel wire of length 2 metres and cross-sectional area of 2 × 10−6 m² is stretched by a force of 400 N. If the Young's modulus of steel is 2
× 1011 N m−2, calculate the extension of the wire. [5]
(b) Explain in detail the
classification of solids with respect to atomic arrangements. [3]
Q.2
(a) Water flows through a pipe
with a diameter of 0.05 m at a velocity of 2 m s−1. If the pipe narrows to a
diameter of 0.03 m, calculate the velocity of water at the narrow section. [5]
(b) What is Archimedes'
principle? Explain it in detail for finding upthrust.
[3]
Q.3
(a) A gas occupies 6.0 L of
volume at a pressure of 12 atm. What will be the volume of gas if the pressure
is increased to 2.0 atm, assuming that temperature
remains constant? [5]
(b) Explain first law of
thermodynamics in detail. Give an example in support of your explanation. Give
its two applications. [3]
Q.4
(a) A Carnot engine is
operating between a high temperature reservoir at 600 K and a low temperature
reservoir at 300 K. Calculate:
(i) the maximum
possible efficiency
(ii) the amount of work output if the engine absorbs
500 J of heat from the high temperature reservoir. [5]
(b) What is Carnot engine?
Describe Carnot cycle. State Carnot theorem and derive an expression for
efficiency of Carnot engine. [3]
Q.5
(a) A block of wood of mass 10
kg and density of 600 kg m−3 is floating in water. Calculate the buoyant force acting
on the block. (Density of water = 1000 kg m−3) [5]
(b) State and derive the
equation of continuity. Also give some practical applications of Bernoulli's
equation. [3]
— END OF
QUESTION PAPER —
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