The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2>W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hn > W2)
|
(a) |
(b) |
(c) |
(d) |
(a) 
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In an hydrogen atom, the electron revolves around the nucleus in an orbit of radius 0.53 
. Then the electrical potential produced by the nucleus at the position of the electron is
|
(a) – 13.6 V |
(b) – 27.2 V |
(c) 27.2 V |
(d) 13.6 V |
The apparent depth of an object lying in a denser medium is always ......... than the real depth.
The power of an achromatic convergent lens of two lenses is + 2D. The power of convex lens is + 5D. The ratio of dispersive power of convex and concave lens will be
|
(a) 5 : 3 |
(b) 3 : 5 |
(c) 2 : 5 |
(d) 5 : 2 |
When light wave suffers reflection at the interface from air to glass, the change in phase of the reflected wave is equal to
| (a) 0 |
(b) 
|
(c) 
|
(d) 2
|
The earth's magnetic induction at a certain point is 7 × 
. This is to be annulled by the magnetic induction at the centre of a circular conducting loop of radius 5 cm. The required current in the loop is
|
(a) 0.56 A |
(b) 5.6 A |
(c) 0.28 A |
(d) 2.8 A |
