Physics miscellaneous
- When a stone is thrown in the calm water of a pond the waves produced on the surface of water in the pond are
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The waves produced on the surface of water in the pond is an example of transverse waves as particles of the medium do not move along with the wave. Only the disturbance is carried forward. Another example of such waves is the vibrations of a string.
Correct Option: B
The waves produced on the surface of water in the pond is an example of transverse waves as particles of the medium do not move along with the wave. Only the disturbance is carried forward. Another example of such waves is the vibrations of a string.
- Dioptere is the unit of
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A dioptre or diopter, is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres). It is thus a unit of reciprocal length.
Correct Option: A
A dioptre or diopter, is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres). It is thus a unit of reciprocal length.
- A man standing on a edge of a cliff throws a stone vertically upwards with a certain speed. He then throws another stone downwards with the same speed. Find the ratio of the speeds of the two stones when they hit the ground.
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The stone which is throws upward will have the same velocity of u at the point of its original position when it is falling down. Another stone is thrown downwards with u. So the velocity of both the stones is equal at the original point. Hence both stone will hit the ground with same velocity. So the ratio between the speeds of two stones will be 1:1
Correct Option: A
The stone which is throws upward will have the same velocity of u at the point of its original position when it is falling down. Another stone is thrown downwards with u. So the velocity of both the stones is equal at the original point. Hence both stone will hit the ground with same velocity. So the ratio between the speeds of two stones will be 1:1
- Gas thermometers are more sensitive than the liquid thermometers because the gases
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Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermo-meter.
Correct Option: A
Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermo-meter.
- When the milk is churned vigorously the cream from it is separated out due to
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The separation of cream from milk is based on the fact that when liquids of different specific gravity revolve around the same centre at the same distance with the same velocity, a greater centrifugal force is exerted on the heavier liquid than on the lighter one. Milk consists of two liquids of different specific gravity: fat and milk serum.
Correct Option: D
The separation of cream from milk is based on the fact that when liquids of different specific gravity revolve around the same centre at the same distance with the same velocity, a greater centrifugal force is exerted on the heavier liquid than on the lighter one. Milk consists of two liquids of different specific gravity: fat and milk serum.