A certain mass of solid substance is heated for a period of 50 min. Its heating curve is shown below :

From the graph, which one of the following statement is correct?

1. The boiling point of the given substance is 40°C.
2. The specific latent heat of fusion of substance is the same as the specific latent heat of vaporisation.
3. The substance has a higher specific heat capacity in solid state than that in liquid state.
4. The substance has a lower specific heat capacity in solid state than that in liquid state.

In the circuit shown, lamps L₁ and L₂, are identical. The sliding contact at O moved towards Q, then which of the statements about the effect on the brightness in L₂ is correct?

1. Initially it has no light, then its brightness increases gradually and becomes equal to that of L₁
2. Initially it is same as that of L₁, and finally become half as that of L₁
3. Initially it is half as that of L₁ and finally becomes equal to that of L₁.
4. Initially it is half as that of L₁ and finally becomes zero.

In which of the following figures shown, will the sound of a tuning fork hit with rubber pad at end A be heard maximum at end B?

1. I
2. II
3. Both I and II
4. Cannot be decided

The force of 20 N is applied at distance of 40 cm from the axis. The moment of force is

1. 8 N-m
2. 0.4 N-m
3. 8.5 N-m
4. 20 N-m