MODEL QUESTION PAPER PHYSICS +1

SET 1

1. A body is thrown vertically upward into air with an initial velocity ‘V0’
a) What will be the velocity at its maximum height. Why? (1)
b) Find the time taken to reach maximum height? (2)
c) When air resistance is taken into consideration, it is found that time of ascent is less than time of
descent. Is this statement true? Justify (2)
2. When a train traveling at a high speed with its whistle blowing, approaches to you on the platform, the
pitch of sound whistle appears to rise
a) Which is the scientific phenomenon behind it? (1)
b) State that phenomenon (1)
c) A person is standing on a railway platform. An engine while approaching the platform blow, a whistle
of pitch 660Hz. The speed of engine is 72Km/hr. Calculate the apparent pitch of whistle as heard by the
person. Velocity of sound is 340m/s. (3)
3. Modulus of elasticity of a material is the ratio of stress and strain
a) Young’s Modulus for a perfectly rigid body is------------------------ (1)
b) One end of a rope of length 4.5cm and diameter 6mm is fixed on the branch of a tree. A monkey
weighing 100N jump to catch tree. Find elongation (given Y=9.8x1011N/m) (3)
4. Two cricket balls are colliding with each other
a) Name the collision (1/2)
b) Say whether the law of conservation of kinetic energy hold good in this case. Why? (1)
c) State and prove other conservation law applicable here. (2 1/2)
5. Escape velocity of objects in a planet depends on mass and size of the planet
a) Write down the expression for escape velocity on the surface of earth (1)
b)Give reasons why the moon does not have an atmosphere around it (2)
6. a) Heat from the sun reaches the earth. Which method of heat transmission occurs in this case. (1/2)
b) Thermal conductivity of Aluminium is 205Jm-1s-1deg-1.What is meant by this (2)
c) A man wears some woolen cloth of thickness 3mm in winter. Thermal conductivity of the material of
cloth is 0.05Wm-1deg-1. If the body temperature and outside temperature are 350C and 100C
respectively, how much amount of heat is lost per square meter of the clothes from his body in one
hour? (3)
7. Water boils at 1000c and is converted into vapour
a) Which thermodynamic process involves in this statement. Explain thermodynamic process (1 1/2)
b) Obtain a mathematical formula for work done in the above thermodynamic process (2 1/2)
c) Three moles of ideal gas kept at a constant temperature of 300K are compressed from a volume of
4 litres to 1 litre. Calculate work done during this process. (2)
8. A mass is suspended at one end of a spring and the other end of the spring is firmly found at the ceiling.
If the mass is slightly depressed and released, it will execute oscillations.
a) Write down the expression for frequency of oscillation of the mass (1)
b) If the spring is cut into two equal halves and one half of the spring is used to suspend the same mass,
then obtain an expression for the ratio of periods of oscillation in two cases. (2)
c) If the system is completely immersed in water, then what happens to the oscillations? (2)
9. Give examples for the following
a) A dimensionless, unitless quantity (1/2)
b) A dimensionless physical quantity but having unit with SI system (1/2)
c) Two physical quantities which have the same dimensions (1)
10. Water cannot wet the feather of ducks. A physical quantity called angle of contact, determines
whether a liquid will spread on the surface of a solid or it will form droplets on it
a) Define angle of contact (1)
b) A wire of internal radius 3cm and external radius 3.2cm is rested on the surface of a liquid and
then raised. An extra pulling force equivalent to the weight 3.03gm is required before the film breaks than
it is after. Calculate surface tension of the liquid. (2)
c) Derive an expression for the capillary height of a liquid in a narrow tube. (3)
OR
To keep a piece of paper horizontal .You should blow over, not under it
a) Which is the principle behind it (1)
b) Stat the principle and derive it (3)
c) A cylindrical tube has a cross section of 8cm2 on one end and other end has a coss section of 12cm2. If
the liquid flows inside the tube is 0.5m/s. What is the speed of ejection of the liquid through the other
end. (2)
11. Moment of inertia of a disc about diameter is (MR2)/4. where M is the mass and R is the radius of the
disc.
a) What is the moment of inertia of the disc about a tangent in its plane (1)
b) Which theorem is used for the above calculation (1/2)
c) State the theorem (1 1/2)
12. a) State the law of equipartition of energy (1 1/2)
b) A flask contains argon and chlorine in the ratio of 2:1 by mass. The temperature of the mixture is 270C
Obtain the ratio of root mean square velocity of molecules of two gases. Atomic mass of argon=39.9U,
Molecular mass of Chlorine=70.9U (2)
13. A body is projected into the air with a velocity
a) Which component of velocity is constant throughout the projectile motion (1)
b) Obtain an expression for time of flight and horizontal range (2)
c) Find the minimum velocity with which a stone is projected in order to hit a target 20m away
(g=9.8m/s2) (2)