
- ASilicon
- BPolymer
- CNichrome
- DCopper

Explanation:
For metals, the temperature coefficient of resistivity is positive. At lower temperatures, the resistivity of a pure metal increases as a higher power of temperature. So, the answer is copper, which is a metal.
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A particle which has zero rest mass and non-zero energy and momentum must travel with a speed
|
(a) Equal to c, the speed of light in vacuum |
(b) Greater than c |
|
(c) Less than c |
(d) Tending to infinity |
A coil of area
has 500 turns. Magnetic field of
is perpendicular to the coil. The field is reduced to zero in 0.1 second. The induced e.m.f. in the coil is
|
(a) 1 V |
(b) 5 V |
(c) 50 V |
(d) Zero |
A positively charged thin metal ring of radius R is fixed in the xy - plane with its centre at the O. A negatively charged particle P is released from rest at the point (0, 0, where
. Then the motion of P is
|
(a) Periodic for all values of |
|
(b) Simple harmonic for all values of satisfying 0 < |
|
(c) Approximately simple harmonic provided |
|
(d) a, c |
In the given figure, which of the diodes are forward biased ?
1.2.
3.
4.
5.
|
(a) 1, 2, 3 |
(b) 2, 4, 5 |
(c) 1, 3, 4 |
(d) 2, 3, 4 |
The rays of different colours fail to converge at a point after going through a converging lens. This defect is called:
In short wave communication waves of which of the following frequencies will be reflected back by the ionospheric layer, having electron density 1011 per m3
|
(a) 2 MHz |
(b) 10 MHz |
(c) 12 MHz |
(d) 18 MHz |
Doping of intrinsic semiconductor is done
|
(a) To neutralize charge carriers |
|
(b) To increase the concentration of majority charge carriers |
|
(c) To make it neutral before disposal |
|
(d) To carry out further purification |