The valence band and the conductance band of a solid overlap at low temperature. The solid may be
Options
(a) A metal (b) A semiconductor (c) An insulator (d) None of these
Correct […]
If the wavelength of light in vacuum be, the wavelength in a medium of refractive index µ will be
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(a) µλ (b) λ / µ (c) λ / µ² (d) µ²λ
Correct […]
When a radioactive substance emits an ∝ particle, its position in the periodic table is lowered by
Options
(a) one place (b) two places (c) three places (d) four places
Correct Answer:
two […]
A particle is moving with a uniform velocity along a straight line path. A force is not required to
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(a) increase its speed (b) decrease the momemtum (c) change the direction (d) […]
The rest mass of a body is m1. It moves with a velocity of 0.6c, then its relativistic mass if m then
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(a) m = m1 (b) m < m1 (c) m […]
A black body is heated from 27° C to 127° C. The ratio of their energies of radiations emitted will be
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(a) 3 : 4 (b) 9 : 16 (c) 27 : […]
The distance of a geo-stationary satellite from the centre of the earth is nearest to(where R=6400 km)
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(a) 5 R (b) 7 R (c) 10 R (d) 18 R
Correct Answer:
7 […]
If the lattice parameter for a crystalline structure is 3.6 Å, then the atomic radius in fcc crystal is
Options
(a) 2.92 Å (b) 1.27 Å (c) 1.81 Å (d) 2.1 Å
Correct […]
Reactance of a capacitor of capacitance C µF for A.C freqency (400 / π) Hz is 25 ohm. The value of C is
Options
(a) 25 µF (b) 100 µF (c) 75 µF […]
A ball is dropped from a height of 20 cm. Ball rebounds to a height of 10cm. What is the loss of energy?
Options
(a) 25% (b) 75% (c) 50% (d) 100%
Correct […]
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