Zener breakdown in a semi-conductor diode occurs when
|
(a) Forward current exceeds certain value |
(b) Reverse bias exceeds certain value |
|
(c) Forward bias exceeds certain value |
(d) Potential barrier is reduced to zero |
(b) Reverse bias exceeds certain value
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Assertion : A person touching a high power line gets stuck with the line.
Reason : The current carrying wires attract the man towards it.
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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. |
Plutonium decays with a half-life of 24000 years. If the plutonium is stored for 72000 years, then the fraction of plutonium that remains is
|
(a) |
(b) |
(c) |
(d) |
Let V and H be the vertical and horizontal components of earth's magnetic field at any point on earth. Near the north pole
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(a) V >> H |
(b) V << H |
(c) V = H |
(d) V = H = 0 |
A hollow conducting sphere is placed in an electric field produced by a point charge placed at P as shown in figure. Let 
be the potentials at points A, B and C respectively. Then
|
(a) |
(b) |
(c) |
(d) |
The amplification factor of a triode is 50. If the grid potential is decreased by 0.20 V, what increase in plate potential will keep the plate current unchanged
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(a) 5 V |
(b) 10 V |
(c) 0.2 V |
(d) 50 V |
The wavelength of maximum energy, released during an atomic explosion, was 2.93 × 10–10 m. Given that the Wien's constant is 2.93 × 10–3 m K, the maximum temperature attained must be of the order of
|
(a) 10–7 K |
(b) 107 K |
(c) 10–13 K |
(d) 5.86 × 107 K |
Polarising angle for water is 53°4'. If light is incident at this angle on the surface of water and reflected, the angle of refraction is
|
(a) 53°4' |
(b) 126°56' |
(c) 36°56' |
(d) 30°4' |
