When a semiconductor is heated, its resistance
|
(a) Decreases |
(b) Increases |
(c) Remains unchanged |
(d) Nothing is definite |
When a semiconductor is heated, its resistance
|
(a) Decreases |
(b) Increases |
(c) Remains unchanged |
(d) Nothing is definite |
(a) Decreases
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An electron and proton have the same de-Broglie wavelength. Then the kinetic energy of the electron is
|
(a) Zero |
|
(b) Infinity |
|
(c) Equal to the kinetic energy of the proton |
|
(d) Greater than the kinetic energy of the proton |
Two charged spheres separated at a distance d exert a force F on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force (if all conditions are same)
|
(a) |
(b) F |
(c) 2F |
(d) 4F |
A strip of copper and another of germanium are cooled from room temperature to 80 K. The resistance of
|
(a) Each of these increases |
|
(b) Each of these decreases |
|
(c) Copper strip increases and that of germanium decreases |
|
(d) Copper strip decreases and that of germanium increases |
Force between two identical bar magnets whose centres are r metre apart is 4.8 N, when their axes are in the same line. If separation is increased to 2r, the force between them is reduced to
|
(a) 2.4N |
(b) 1.2N |
(c) 0.6N |
(d) 0.3N |
The magnetic field due to a straight conductor of uniform cross section of radius a and carrying a steady current is represented by
|
(a) |
(b) |
(c) |
(d) |
X-rays of wavelength 0.1 Å allowed to fall on a metal get scattered. The wavelength of scattered radiation is 0.111 Å. If h = 6.624 × 10–34 J-s and m0 = 9 × 10–31 kg, then the direction of the scattered photons will be
| (a) cos–1 (0.547) | (b) cos–1 (0.4484) | (c) cos–1 (0.5) | (d) cos–1 (0.3) |
The square root of the product of inductance and capacitance has the dimension of
|
(a) Length |
(b) Mass |
(c) Time |
(d) No dimension |