Electromagnetic Waves — Physics STD 12 Science — Question

A large nonconducting sheet M is given a uniform charge density. Two uncharged small metal rods A and B are placed near the sheet as shown in figure:

1. M attracts A.
2. M attracts B.
3. A attracts B.
4. B attracts A.

The Sun receives its radiation energy from :

Polarisation of light was first successfully explained by:

A positively charged particle projected towards east is deflected towards north by a magnetic field. The field may be:

Electrically, photons are:

If a magnet is plugged into a coil, then the magnitude of induced emf does not depend upon:

A fish rising vertically up towards the surface of water with speed 3 ms^–1 observes a bird diving vertically down towards it with speed 9 ms^–1. The actual velocity of bird is

(a) 4.5 ms–1

(b) 5. ms–1

(c) 3.0 ms–1

(d) 3.4 ms–1

Force between two charges at rest is____?

A parallel plate capacitor is charged. If the plates are pulled apart:

The half-life of a radioactive substance against a-decay is 1.2 . What is the decay rate for 4  atoms of the substance

(a) 4.6	(b) 2.3
(c) 4.6	(d) 2.3