A soap bubble is given a negative charge, then its radius
|
(a) Decreases |
|
(b) Increases |
|
(c) Remains unchanged |
|
(d) Nothing can be predicted as information is insufficient |
(b) Increases
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The magnetic compass is not useful for navigation near the magnetic poles because
|
(a) The magnetic field near the poles is zero |
|
(b) The magnetic field near the poles is almost vertical |
|
(c) At low temperature, the compass needle looses its magnetic properties |
|
(d) Neither of the above |
A sphere of 4 cm radius is suspended within a hollow sphere of 6 cm radius. The inner sphere is charged to potential 3 e.s.u. and the outer sphere is earthed. The charge on the inner sphere is
|
(a) 54 e.s.u. |
(b) |
(c) 30 e.s.u. |
(d) 36 e.s.u. |
The magnetic flux linked with a circuit of resistance 100 ohm increases from 10 to 60 webers. The amount of induced charge that flows in the circuit is (in coulomb)
|
(a) 0.5 |
(b) 5 |
(c) 50 |
(d) 100 |
Angle of prism is A and its one surface is silvered. Light rays falling at an angle of incidence 2A on first surface return back through the same path after suffering reflection at second silvered surface. Refractive index of the material of prism is
|
(a) 2 sin A |
(b) 2 cos A |
(c) |
(d) tan A |
A particle of charge q and mass m is moving along the x -axis with a velocity v and enters a region of electric field E and magnetic field B as shown in figure below for which figure the net force on the charge may be zero
|
(a)
|
(b)
|
(c)
|
(d)
|
The fine powder of a coloured glass is seen as
|
(a) Coloured |
(b) White |
|
(c) That of the glass colour |
(d) Black |
Average energy stored in a pure inductance L when a current i flows through it, is
|
(a) |
(b) |
(c) |
(d) |
