According to Joule's law, if the potential difference across a conductor having a material of specific resistance remains constant, then the heat produced in the conductor is directly proportional to
|
(a) ρ |
(b) |
(c) |
(d) |
(d) 
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Young's experiment is performed in air and then performed in water, the fringe width
|
(a) Will remain same |
(b) Will decrease |
(c) Will increase |
(d) Will be infinite |
A point charge is kept at the centre of a metallic insulated spherical shell. Then
|
(a) Electric field out side the sphere is zero |
(b) Electric field inside the sphere is zero |
|
(c) Net induced charge on the sphere is zero |
(d) Electric potential inside the sphere is zero |
The dispersive powers of glasses of lenses used in an achromatic pair are in the ratio 5 : 3. If the focal length of the concave lens is 15 cm, then the nature and focal length of the other lens would be
|
(a) Convex, 9 cm |
(b) Concave, 9 cm |
(c) Convex, 25 cm |
(d) Concave, 25 cm |
A current flows in a conductor from east to west. The direction of the magnetic field at a points above the conductor is .....
|
(a) Towards north |
(b) Towards south |
(c) Towards east |
(d) Towards west |
The maximum magnification that can be obtained with a convex lens of focal length 2.5 cm is (the least distance of distinct vision is 25 cm)
|
(a) 10 |
(b) 0.1 |
(c) 62.5 |
(d) 11 |
Two positive point charges of 12 μC and 8 μC are 10cm apart. The work done in bringing them 4 cm closer is
|
(a) 5.8 J |
(b) 5.8 eV |
(c) 13 J |
(d) 13 eV |
