Current Electricity — Physics STD 12 Science — Question

Two waves are said to be coherent :

In reverse biasing:

If a diamagnetic substance is brought near north or south pole of a bar magnet, it is

(a) Attracted by the poles

(b) Repelled by the poles

(c) Repelled by the north pole and attracted by the south pole

(d) Attracted by the north pole and repelled by the south pole

The work done in placing a charge of 8 ×   coulomb on a condenser of capacity 100 micro-farad is

(a) 32

(b) 16

(c) 3.1

(d) 4

......... Charge is produced by friction

A body is rotating uniformly about a vertical axis fixed in an inertial frame. The resultant force on a particle of the body not on the axis is:

1. Vertical.
2. Horizontal and skew with the axis.
3. Horizontal and intersecting the axis.
4. None of these.

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)

Let p and E denote the linear momentum and energy of a photon. If the wavelength is decreased:

1. Both p and E increase.
2. P increases and E decreases.
3. P decreases and E increases.
4. Both p and E decrease.

Brilliance of diamond is due to

(a) Shape	(b) Cutting
(c) Reflection	(d) Total internal reflection