A substance of mass $m\,kg$ requires a power input of $P$ $watt$ to remain in the molten state at its melting point. When the power is turned off, the substance completely solidifies in time $t\,sec$. The latent heat of fusion of the substance is

Solids expand on heating because ................

$50\, gm$ of copper is heated to increase its temperature by $10\,^oC$. If the same quantity of heat is given to $10\, gm$ of water, the rise in its temperature is ........ $^oC$ (Specific heat of copper $=420\, Joule\, kg^{-1}\,^oC^{-1}$)

Two thermometers $X$ and $Y$ have ice points marked at $15^o$ and $25^o$ and steam points marked as $75^o$ and $125^o$ respectively. When thermometer $X$ measures the temperature of a bath as $60^o$ on it,  ........ $^oC$ would thermometer $Y$ read when it is used to measure the temperature of the same bath ?

Compared to a burn due to water at $100\,^oC,$ a burn due to steam at $100\,^oC$ is

If the volume of a block of metal changes by $0.12\%$ when it is heated through $20^o\,C$, the coefficient of linear expansion (in per $^oC^{-1}$) of the metal is :-