The increase in length of a metal rod depends on:

1. the initial length of the rod only
2. the rise in temperature only
3. the material of the rod only
4. all the above three factors

The correct statement is:

1. Iron rims are cooled before they are placed on the cart wheels.
2. A glass stopper gets tightened on warming the neck of the bottle.
3. Telephone wires sag in winter, but become tight in summer.
4. A little space is left between two rails on a railway track.

Name the three states of matter and distinguish them on the basis of their (i) volume, and (ii) shape

Distinguish between liquid and vapour (or gas) states of matter on the basis of the following factors:

(a) Arrangement of molecules

(b) Inter-molecular separation

(c) Inter-molecular force and

(d) Kinetic energy of molecules