Electromagnetic Waves — Physics STD 12 Science — Question

The energy of a photon is E = hv and the momentum of  photon p =  , then the velocity of photon will be

(a) E/p

(b) Ep

(c)

(d) 3

Coulomb's law is a confirmation of______

Equivalence in the following circuit is:

Identify which of the following statement best describe a nuclear reaction.

In hard X-rays :

An ice cube is suspended in vacuum in a gravity free hall. As the ice melts it.

1. Will retain its cubical shape.
2. Will change its shape to spherical.
3. Will fall down on the floor of the hall.
4. Will fly up.

A steady current i is flowing through a conductor of uniform cross-section. Any segment of the conductor has

(a) Zero charge	(b) Only positive charge
(c) Only negative charge	(d) Charge proportional to current i

Curie temperature is the temperature above which:

A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes place in a plane. It follows that:

1. Its velocity is constant.
2. Its acceleration is constant.
3. Its kinetic energy is constant.
4. It moves in a circular path.

Assertion  :   If different gases are filled turn by turn at the same pressure in the discharge tube the discharge in them takes place at the same potential.

Reason      : The discharge depends only on the pressure of discharge tube and not on the ionisation potential of gas.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.