- Increases.
- Decreases.
- Remains constant.
- Oscillates.
AS it is maintaining its shape so its mass will remain constant which implies that if it shrinks then its volume decreases and to keep the mass constant, its density increases. Also the gravitational potential at the centre of a uniform spherical shell is inversely proportional to the radius of the shell with a negative sign. When a uniform spherical shell gradually shrinks, the gravitational potential at the centre decreases (because of the negative sign in the formula of potential).
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The relaxation time in conductors
|
(a) Increases with the increase of temperature |
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(b) Decreases with the increase of temperature |
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(c) It does not depend on temperature |
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(d) All of sudden changes at 400 K |
A hot electric iron has a resistance of 80 Ω and is used on a 200 V source. The electrical energy spent, if it is used for two hours, will be
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(a) 8000 Wh |
(b) 2000 Wh |
(c) 1000 Wh |
(d) 800 Wh |
What is the equivalent resistance between A and B in the figure below if R = 3Ω
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(a) 9 Ω |
(b) 12 Ω |
(c) 15 Ω |
(d) None of these |
One Tesla is equal to
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(a) |
(b) |
(c) |
(d) |
A NPN transistor conducts when
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(a) Both collector and emitter are positive with respect to the base |
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(b) Collector is positive and emitter is negative with respect to the base |
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(c) Collector is positive and emitter is at same potential as the base |
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(d) Both collector and emitter are negative with respect to the base |
The wavelength of X-rays is of the order of
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(a) Centimetre |
(b) Micron (10-6 m) |
(c) Angstrom (10-10 m) |
(d) Metre |