Quiz
1. Air escaping rapidly from a narrow orifice in an inflated tyre feels cool because
the speed with which it escapes cools it down
of the higher temperature of the surroundings
of sudden expansion causing loss of internal energy
there is no real fall in temperature
of sudden expansion causing loss of internal energy
2. The atmosphere gets heated up mainly by
direct sun's rays
radiation from earth's surface
radiogenic heat (resulting from radioactive decay)
cosmic rays coming from space
radiation from earth's surface
3. The plants in a greenhouse are enclosed in a glass enclosure because
glass allows the heat radiations of shorter wavelengths from the sun to pass through
the plants absorb them - these shorter wavelengths - and reradiate them in the form of longer wavelengths
the longer wavelengths cannot penetrate through the glass walls
All the above
All the above
4. The cover of a solar cooker is made of glass because
it absorbs sun's rays
it reflects sun's rays
it retains the heat inside by the greenhouse effect
it radiates heat better than metals
it retains the heat inside by the greenhouse effect
5. The inside of both the walls of a thermos flask is silvered i.e., on the vacuum side in order to reduce heat loss by
convection
radiation
conduction
All the three
radiation
6. When ice just melts
there is no change in volume
there is no change in temperature
heat is given out
there is no change of state
there is no change in temperature
7. Before the invention of geostationary satellites, television stations could not transmit their programmes to far off places because
these signals are electromagnetic in nature
these are not electromagnetic in nature
their wavelength is very large
they are not reflected by the ionosphere but pass through it
they are not reflected by the ionosphere but pass through it
8. Heat transfer
cools the body that transfers it
heats the body that absorbs the heat
may change the physical state of the substance
All the above
All the above
9. The presence of impurities
lowers the melting point of ice
raises the melting point of ice
has no effect on the melting point of ice
may lower or raise the melting point depending upon the type of impurities
lowers the melting point of ice
10. In a freezer ice cubes will be formed more quickly in trays made of
rubber
plastic
aluminium
wood
aluminium
11. Water kept in an earthen pot is less cool on rainy days than in summer because during the rainy days
the pores in the pot are closed
rain water stops oozing out from the pores
the water that oozes out does not evaporate quickly because of the large percentage of moisture in the air
surface of the pot becomes damp
the water that oozes out does not evaporate quickly because of the large percentage of moisture in the air
12. Tap water is placed in an open pad and allowed to evaporate. After some time the temperature of water
increases to a great extent
increases slightly
decreases slightly
decreases rapidly
decreases slightly
13. In hot climatic conditions, the buildings are painted white because
white paint is economical
it does not fade off
it does not crack with higher temperature
white coating is a bad conductor of heat and reflects heat rays that fall on it, thus keeping the inside cool
white coating is a bad conductor of heat and reflects heat rays that fall on it, thus keeping the inside cool
14. The evaporation rate depends on
the nature of the liquid
area of the exposed surface of the liquid
temperature of air and of the liquid
All the above
All the above
15. The rate of cooling of a hot body depends on
the nature of the radiating surface
area of the radiating surface
temperature difference between the body and the surroundings
All the above
All the above
Sure, here is the rest of the MCQs from question number 16 in the specified HTML format:
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16. When we sweat, we feel comfortable under a fan because
the air circulated by the fan is cool
the fan produces convection currents of air
the air circulated by the fan quickens the evaporation of the moisture on our skin
the air takes away the heat from our body
the air circulated by the fan quickens the evaporation of the moisture on our skin
17. The hygrometer is an apparatus used for finding the
temperature of air
intensity of light
density of a liquid
relative humidity of the atmosphere
relative humidity of the atmosphere
18. In a refrigerator, the refrigerant is
Nitrogen
Oxygen
Chlorine
Freon
Freon
19. Which of the following is known as freon?
Liquid ammonia
Carbon tetrafluoride
Dichloro-difluoro-methane
Sulphur dioxide
Dichloro-difluoro-methane
20. Increase in pressure
has no effect on the boiling point of a liquid
raises the boiling point of a liquid
lowers the boiling point of a liquid
increases the volume of a liquid
raises the boiling point of a liquid
21. The pressure of air at high altitude is less than the atmospheric pressure at the sea level. Hence the boiling point of water at a hill top
is more than at sea level
is equal to that at sea level
is less than at sea level
depends on the surrounding temperature
is less than at sea level
22. Increase in pressure
increases the melting point of ice
decreases the melting point of ice
has no effect on the melting point of ice
increases the volume of the ice
decreases the melting point of ice
23. Two tumblers stuck together can be separated by
pouring ice cold water into the inner tumbler
pouring ice cold water on the outer tumbler
pouring hot water into the inner tumbler
dipping both the tumblers in hot water
pouring ice cold water into the inner tumbler
24. Skating on ice is possible because
the surface of ice is smooth
ice is cold
the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
the pressure on the ice due to skate raises its melting point
the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
25. Of the following types of electromagnetic radiation which has the longest wavelength?
ultraviolet rays
gamma rays
radio waves
infrared waves
radio waves
26. Of the following which has got the highest frequency?
ultraviolet rays
gamma rays
radio waves
infrared waves
gamma rays
27. Radio waves sent out by radio stations are reflected by
troposphere
stratosphere
mesosphere
ionosphere
ionosphere
28. The maximum range of most TV signals is from 121 to 240 km only because
the curvature of earth limits the range of reception
the signals are weak
the signals are absorbed by air
the antennae are not powerful enough
the curvature of earth limits the range of reception
29. Less dew is formed on cloudy nights because
there is no moisture in the atmosphere
clouds absorb the falling dew
objects emit radiant energy very fast on such nights
objects lose less radiant energy
objects lose less radiant energy
30. In a refrigerator cooling is produced by
the ice that deposits on the freezer
the evaporation of a volatile liquid
None of the above
Both A. and B.
the evaporation of a volatile liquid
