Which one is correct relation for thermionic emission
|
(a) |
(b) |
(c) |
(d) |
Which one is correct relation for thermionic emission
|
(a) |
(b) |
(c) |
(d) |
(b)
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The graph between the instantaneous concentration (N) of a radioactive element and time (t) is
|
(a) |
(b) |
(c) |
(d) |
A rod of length 20 cm is rotating with angular speed of 100 rps in a magnetic field of strength 0.5 T about it’s one end. What is the potential difference between two ends of the rod
|
(a) 2.28 V |
(b) 4.28 V |
(c) 6.28 V |
(d) 2.5 V |
The light reflected by a plane mirror may form a real image
|
(a) If the rays incident on the mirror are diverging |
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(b) If the rays incident on the mirror are converging |
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(c) If the object is placed very close to the mirror |
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(d) Under no circumstances |
A charge of Q coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself
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(a) Uniformly in the metal object |
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(b) Uniformly on the surface of the object |
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(c) Such that the potential energy of the system is minimised |
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(d) Such that the total heat loss is minimised |
Assertion : Microwave communication is preferred over optical communication.
Reason : Microwaves provide large number of channels and band width compared to optical signals.
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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 electrical circuit used to get smooth dc output from a rectifier circuit is called
| (a) Oscillator | (b) Filter | (c) Amplifier | (d) Logic gates |
The working of dynamo is based on principle of
|
(a) Electromagnetic induction |
(b) Conversion of energy into electricity |
|
(c) Magnetic effects of current |
(d) Heating effects of current |
The reverse biasing in a PN junction diode
| (a) Decreases the potential barrier |
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(b) Increases the potential barrier |
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(c) Increases the number of minority charge carriers |
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(d) Increases the number of majority charge carriers |