Question 11 : oil raise up the wick in a lamp. The principle involves
1. the diffusion of oil through the wick
2. the liquid state of oil
3. capillary action phenomenon
4. volatility of oil
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Question 12 : Rectifiers are used to convert
1. Direct current to Alternating current
2. Alternating current to Direct current
3. high voltage to low voltage
4. low voltage to high voltage
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Question 13 : Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
1. Water[comma] iron and air
2. Iron[comma] air and water
3. Air[comma] water and iron
4. Iron[comma] water and air
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Question 14 : Radiocarbon is produced in the atmosphere as a result of
1. collision between fast neutrons and nitrogen nuclei present in the atmosphere
2. action of ultraviolet light from the sun on atmospheric oxygen
3. action of solar radiations particularly cosmic rays on carbon dioxide present in the atmosphere
4. lightning discharge in atmosphere
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Question 15 : Mica is used in electrical appliances such as electric iron because mica is
1. a good conductor of heat but a bad conductor of electricity
2. a bad conductor of heat but a good conductor of electricity
3. a good conductor of heat as well as electricity
4. a bad conductor of heat as well as electricity
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Question 16 : Intensity of sound at a point is ____ its distance from the source.
1. directly proportional to
2. inversely proportional to
3. directly proportional to square of
4. inversely proportional to square of
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Question 17 : Optical fibre works on the
1. principle of refraction
2. total internal reflection
3. scattering
4. interference
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Question 18 : Siphon will fail to work if
1. the densities of the liquid in the two vessels are equal
2. the level of the liquid in the two vessels are at the same height
3. both its limbs are of unequal length
4. the temperature of the liquids in the two vessels are the same
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Question 19 : Pa(Pascal) is the unit for
1. thrust
2. pressure
3. frequency
4. conductivity
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Question 20 : Mirage is due to
1. unequal heating of different parts of the atmosphere
2. magnetic disturbances in the atmosphere
3. depletion of ozone layer in the atmosphere
4. equal heating of different parts of the atmosphere
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