The specific heat of alcohol is about half that of water. Suppose you have identical masses of alcohol and water. The alcohol is initially at temperature $T_A$. The water is initially at a different temperature $T_W.$ Now the two fluids are mixed in the same container and allowed to come into thermal equilibrium, with no loss of heat to the surroundings. The final temperature of the mixture will be :-

A geyser heats water flowing at the rate of $3.0$ litres per minute from $27\,^{\circ} C$ to $77\,^{\circ} C$ If the geyser operates on a gas burner, what is the rate of consumption (in $g/min$) of the fuel if its heat of combustion is $4.0 \times 10^{4}\; J / g$ ?

$4200\, J$ of work is required for

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  $(g = 10\,m/{s^2})$

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