The curve between current (i) and potential difference (V) for a photo cell will be
|
(a)
|
(b)
|
(c)
|
(d)
|
The curve between current (i) and potential difference (V) for a photo cell will be
|
(a)
|
(b)
|
(c)
|
(d)
|
(d)

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Two spheres of radius a and b respectively are charged and joined by a wire. The ratio of electric field of the spheres is
|
(a) a/b |
(b) b/a |
(c) |
(d) |
Work function of lithium and copper are respectively 2.3 eV and 4.0 eV. Which one of the metal will be useful for the photoelectric cell working with visible light ? (h = 6.6 × 10–34 J-s, c = 3 × 108 m/s)
|
(a) Lithium |
(b) Copper |
(c) Both |
(d) None of these |
A person is in a room whose ceiling and two adjacent walls are mirrors. How many images are formed
| (a) 5 | (b) 6 | (c) 7 | (d) 8 |
Thermocouple is a device for the measurement of
|
(a) Absolute temperature of a metal |
|
(b) The temperature difference between two substances |
|
(c) The couple acting on a wire |
|
(d) Thermal conductivity of a substance |
A magnetic needle suspended horizontally by an unspun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from
| (a) The torsion of the silk fibre |
| (b) The force of gravity |
|
(c) The horizontal component of earth's magnetic field |
| (d) All the above factors |
The frequencies of X-rays, g-rays and ultraviolet rays are respectively a, b and c. Then
|
(a) a < b, b > c |
(b) a > b, b > c |
(c) a > b, b < c |
(d) a < b, b < c |
For an isotropic medium B, m, H and M are related as (where B,
and M have their usual meaning in the context of magnetic material
|
(a) (B – M) = |
(b) |
(c) |
(d) |