Chapter 8 : Mechanics of
- Why do divers in deep sea and mountaineers at high altitude
wear 'pressurized' suits ?
The pressure is much different than sea-level atmospheric pressure.
How did Archimedes convince King Hero that the Crown made by the Goldsmith was not of pure gold ? Explain.
Ans : The pure gold crown will weigh more than impure one of same size in water.
Water taken in the bore of a capillary laid in horizontal position does not flow but can leak
away, explain. If mercury was taken instead of water, then what would happen ?
Ans : As there is no pressure difference applied water cannot flow, but it leaks away as adhesive
forces are greater than cohesive forces. For mercury it is te reverse case.
Chapter 9 : Wave
Distinguish between transverse and longitudinal waves.
Show that the linear, harmonic, progressive wave equation . is periodic in time.
Explain the change in phase of a wave reflected from a boundary.
Chapter 10 : Sound Waves
What are beats of sound, how are they produced ? Does a Guitarist use beats, if so how ?
What happens to the pitch of a horn sounded by an approaching motorist, a receding one? why?
Are the standing waves really waves, explain ?
When one tunes a radio or a T.V., which phenomenon is being used. Explain.
Chapter 11 : Temperature and Thermometers
Explain the concept of temperature.
If the temperature of an object is 500C, then what will this temperature be in
0F & 0R ?
Ans : 122
0F, 40 0R
Chapter 12 : Thermal Expansions of Solids, Liquids and Gases
- Why the rails on which railway carriages move are laid with
small gaps between them ?
Why do metal pendulum clocks fall behind the time in summer and run ahead of the time in winter?
The oil tankers (ships used for transporting oil) do not have their tanks completely filled oil, why ?
Pressure cookers used for cooking are provided with safety valves, why ?
A hollow metal sphere is floating on water at
00C. If the temperature of water rises to
q0C, the sphere just submerges in water. Neglect the expansion of sphere. Find expression for
determining coefficient of cubical expansion of water.
Ans : Density of water at 00C , d = density of sphere.
Moon has no atmosphere, explain why is it so ?
Estimate the temperature at which oxygen molecules can escape from Earth. (g = 10
m/s, Re = 6.4 106 m, R = 8.3 Joule/mole 0K, Molecular wt. of
O2 = 32)
Ans : T = 1.65 105 K
13 : Calorimetry and Mechanical Equivalent of heat
How much heat is released when steam of mass 1 gm at
1000C is converted to ice at
00C. 'L' of condensation of steam is 540 calorie / gm, freezing of water is 80 calorie / gm and specific heat
of water is 1 calorie / gm 0C?
Why are burns caused by steam more severe than by water, both at
Chapter 14 : Heat Transfer
A piece of metal is felt to be colder than a piece of wood through both are at room temperature
When a liquid is being heated the topmost layer is at highest temperature. State true or false
Why do the warm blooded creatures experience 'heat' and 'cold' ?
Chapter 15 : Thermodynamics
When a moving car stops all its K.E. is converted into heat. "It is possible to give the car K.E.
by supplying heat to it", is the statement true ? Which law is the reason behind this possibility ? But
can this possibility be realized ? Why not ?
When one whistles the air blown feels cooler on one's palms but when air is exhaled from the
mouth it feels warmer, why ?
Carnot's ideal heat engine is less than 100% efficient, why ?