Electric power is transmitted over long distances through conducting wires at high voltage because
|
(a) High voltage travels faster |
|
(b) Power loss is large |
|
(c) Power loss is less |
|
(d) Generator produced electrical energy at a very high voltage |
(c) Power loss is less
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The frequency of a light ray is 6 
. Its frequency when it propagates in a medium of refractive index 1.5, will be
|
(a) 1.67 |
(b) 9.10 |
(c) 6 |
(d) 4 |
The shortest wavelength in the Lyman series of hydrogen spectrum is 912 Å corresponding to a photon energy of 13.6 eV. The shortest wavelength in the Balmer series is about
| (a) 3648 Å | (b) 8208 Å | (c) 1228 Å | (d) 6566 Å |
In a common base amplifier circuit, calculate the change in base current if that in the emitter current is 2 mA and a = 0.98
|
(a) 0.04 mA |
(b) 1.96 mA |
(c) 0.98 mA |
(d) 2 mA |
When a ray of light passes from a denser to a rarer medium:
Assertion : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased.
Reason : On increasing temperature, conductivity of metallic wire decreases.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
To get three images of a single object, one should have two plane mirrors at an angle of
|
(a) 30° |
(b) 60° |
(c) 90° |
(d) 150° |
A charge +Q is moving upwards vertically. It enters a magnetic field directed to the north. The force on the charge will be towards
|
(a) North |
(b) South |
(c) East |
(d) West |