The relative humidity on a day, when partial pressure of water vapour is $0.012 \times {10^5}\,Pa$ at $12°C$ is ......... $\%$ (take vapour pressure of water at this temperature as $0.016 \times {10^5}\,Pa$)

Latent heat of ice is $80 \,cal/gm$. A man melts $60\, g$ of ice by chewing in $1$ minute. His power is ........ $W$

The specific heat of a metal at low temperatures varies according to $S = aT^3$ where a is a constant and $T$ is the absolute temperature. The heat energy needed to raise unit mass of the metal from $T = 1 K$ to $T = 2 K$ is

Water of volume $2\, L$ in a closed container is heated with a coil of $1\,kW$. While water is heated, the container loses energy at a rate of $160\, J/s$ . In how much time will the temperature of water rise from $27\,^oC$ to $77\,^oC$ ? (Specific heat of water is $4.2\, kJ/kg$ and that of the container is negligible)

A piece of ice falls from a height $h$ so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of $h$ is

[Latent heat of ice is $3.4 \times 10^{5}\; J / k g$ and $g=10\; N / kg ]$

Heat needed to convert $1$ kilogram ice at $0^o\,C$ to steam at $100^o\,C$ is