Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Heat and work are equivalent. This means:

1. When we supply heat to a body we do work on it.
2. When we do work on a body we supply heat to it.
3. The temperature of a body can be increased by doing work on it.
4. A body kept at rest may be set into motion along a line by supplying heat to it.

Light waves can be polarised because they:

The materials having high resistance to the passage of electricity are called as:

Unpolarized light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam

(a) 75°

(b) 55°

(c) 35°

(d) 15°

Identify the process in which an electron escapes from the metal surface.

The energy emitted by a source is in the form of:

The angular speed of the electron in the nth orbit of Bohr hydrogen atom is?

Serious draw back of the semiconductor device is

(a) They cannot be used with high voltage

(b) They pollute the environment

(c) They are costly

(d) They do not last for long time

One serious drawback of semi-conductor devices is:

For a nucleus to be stable, the correct relation between neutron number N and Proton number Z is

(a) N > Z

(b) N = Z

(c) N < Z

(d) N ≥ Z