Q.1. The clouds float in the atmosphere because of their low:
Ans→ temperature
Q.2. Low temperatures (cryogenies) find application in:
Ans→ space travel, surgery and
magnetic levitation
magnetic levitation
Q.3. When water is heated from 0
degree C to 10 degree C its volume :
degree C to 10 degree C its volume :
Ans→ first decreases and then
increases
increases
Q.4. The change of a solid into
vapour directly is called:
vapour directly is called:
Ans→ sublimation
Q.5. A hollow sphere of radius R, a hollow cube of side R and thin
circular plate of radius R made up of
the some material are all heated to 20 degree C above room temperature. When left to cool in the room, which of them will reach the room temperature first ?
circular plate of radius R made up of
the some material are all heated to 20 degree C above room temperature. When left to cool in the room, which of them will reach the room temperature first ?
Ans→ sphere
Q.6. What is the principle by which
a cooling system (Radiator) in a motor car works ?
a cooling system (Radiator) in a motor car works ?
Ans→ convection
Q.7. Which of the following is the
best conductor of the heat:
best conductor of the heat:
Ans→ silver
Q.8. In the winter season if we
touch two blocks one of iron and
another of wood in the early morning then the block of iron appears to be more cold because:
touch two blocks one of iron and
another of wood in the early morning then the block of iron appears to be more cold because:
Ans→ iron is a good conductor of heat in comparison of the wood
Q.9. The water from a hand pump
is warm in winter because:
is warm in winter because:
Ans→ the temperature inside the
earth is higher than the atmospheric
temperature
earth is higher than the atmospheric
temperature
Q.10. Which colour of heat radiation represents the highest temperature ?
Ans→ white
Q.11. which one of the following
statements is correct ? Transfer of
heat energy from a heater coil to the
cooking vessel takes place through the process of-
statements is correct ? Transfer of
heat energy from a heater coil to the
cooking vessel takes place through the process of-
Ans→ Radiation and convection only
Q.12. How can boilng point of a
liquid be reduced ?
liquid be reduced ?
Ans→ by decreasing the pressure on the liquid
Q.13. The temperature of a body is
an indicator of :
an indicator of :
Ans→ the average kinetic energy of
the molecules of the body
the molecules of the body
Q.14. At normal temperature, due
to a puncture the compressed air inside the tube of a car wheel suddenly starts coming out. Then the air inside the tube :
to a puncture the compressed air inside the tube of a car wheel suddenly starts coming out. Then the air inside the tube :
Ans→ remains at the same
temperatue
temperatue
Q.15. A real gas can be liquefied
by the application of pressure when its temperature is:
by the application of pressure when its temperature is:
Ans→ at the critical temperature
Q.16. Night are cooler in the
deserts than in the plains because:
deserts than in the plains because:
Ans→ sand radiates heat more
quickly than the earth
quickly than the earth
Q.17. Clear night are colder than
cloudy nights because of :
cloudy nights because of :
Ans→ radiation
Q.18. A gas thermometer is more
sensitive than a liquid thermometer
because a gas:
sensitive than a liquid thermometer
because a gas:
Ans→ expands more than a liquid
Q.19. The speed of light with the
rise in the temperature of the medium:
rise in the temperature of the medium:
Ans→ Remains unaltered
Q.20. What is the SI unit of density?
Ans→ Kg/cube meter
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