n identical bulbs, each designed to draw a power p from a certain voltage supply, are joined in series across that supply. The total power which they will draw is
|
(a) |
(b) p/n |
(c) p |
(d) np |
(b) p/n
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Two pure inductors each of self inductance L are connected in parallel but are well separated from each other. The total inductance is
|
(a) 2L |
(b) L |
(c) |
(d) |
A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite sides. Ratio of magnetic fields at these points will be
|
(a) 8 |
(b) 1/2 |
(c) 3 |
(d) 4 |
A combination of two thin convex lenses of focal length 0.3 m and 0.1 m will have minimum spherical and chromatic aberrations if the distance between them is
|
(a) 0.1 m |
(b) 0.2 m |
(c) 0.3 m |
(d) 0.4 m |
A conducting wire is dropped along east-west direction, then
|
(a) No emf is induced |
|
(b) No induced current flows |
|
(c) Induced current flows from west to east |
|
(d) Induced current flows from east to west |
Two bulbs, one of 50 watt and another of 25 watt are connected in series to the mains. The ratio of the currents through them is
|
(a) 2 : 1 |
(b) 1 : 2 |
|
(c) 1 : 1 |
(d) Without voltage, cannot be calculated |
To explain his theory, Bohr used
|
(a) Conservation of linear momentum |
|
(b) Conservation of angular momentum |
|
(c) Conservation of quantum frequency |
|
(d) Conservation of energy |
Assertion : Silicon is preferred over germanium for making semiconductor devices.
Reason : The energy gap for germanium is more than the energy gap of silicon.
|
(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. |
A magnetic needle suspended by a silk thread is vibrating in the earth's magnetic field. If the temperature of the needle is increased by 500°C, then
| (a) The time period decreases | (b) The time period remains unchanged |
| (c) The time period increases | (d) The needle stops vibrating |
