The factor not needed to calculate heat lost or gained when there is no change of state is

Give value of specific heat of gas for isothermal process.

Why water is used as coolant in automobile radiator ?

Three bodies $A, B$ and $C$ of masses $m, m$ and $\sqrt 3\,m$ respectively are supplied heat at a constant rate. The change in temperature $\theta $ versus time $t$ graph for $A, B$ and $C$ are shown by $I, II$ and $III$ respectively. If their specific heat capacities are $S_A, S_B$ and $S_C$ respectively then which of the following relation is correct ? (Initial temperature of body is $0\,^oC$ )

Hailstone at $0°C$ falls from a height of $1\, km$ on an insulating surface converting whole of its kinetic energy into heat. What part of it will melt  $(g = 10\,m/{s^2})$