Explanation:
(d) is based on Joule's Law.
Rest are electrostatic phenomenon.
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The amount of charge required to liberate 9 gm of aluminium (atomic weight = 27 and valency = 3) in the process of electrolysis is (Faraday's number = 96500 coulombs/gm equivalent)
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(a) 321660 coulombs |
(b) 69500 coulombs |
(c) 289500 coulombs |
(d) 96500 coulombs |
Assertion : The earth’s magnetic field does not affect the working of a moving coil galvanometer.
Reason : Earth’s magnetic field is very weak.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
The grid voltage of any triode valve is changed from –1 volt to – 3 volt and the mutual conductance is 3 
mho. The change in plate circuit current will be
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(a) 0.8 mA |
(b) 0.6 mA |
(c) 0.4 mA |
(d) 1 mA |
The curve between current (i) and potential difference (V) for a photo cell will be
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(a)
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(b)
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(c)
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(d)
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Assertion : Silicon is preferred over germanium for making semiconductor devices.
Reason : The energy gap for germanium is more than the energy gap of silicon.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
Wires P and Q have the same resistance at ordinary (room) temperature. When heated, resistance of P increases and that of Q decreases. We conclude that
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(a) P and Q are conductors of different materials |
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(b) P is N-type semiconductor and Q is P-type semiconductor |
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(c) P is semiconductor and Q is conductor |
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(d) P is conductor and Q is semiconductor |
The field normal to the plane of a wire of n turns and radius r which carries a current i is measured on the axis of the coil at a small distance h from the centre of the coil. This is smaller than the field at the centre by the fraction
|
(a) |
(b) |
(c) |
(d) |
In Young’s double slit experiment, the two slits act as coherent sources of equal amplitude A and wavelength l. In another experiment with the same set up the two slits are of equal amplitude A and wavelength l but are incoherent. The ratio of the intensity of light at the mid-point of the screen in the first case to that in the second case is
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(a) 1 : 2 |
(b) 2 : 1 |
(c) 4 : 1 |
(d) 1 : 1 |
