The portion $AB$ of the cooling curve representing the state of matter denotes:

$A$ solid cube having certain fixed melting and boiling points takes heat from some source. The variation of temperature $\theta$ of the cube with the heat supplied $Q$ is shown in the adjoining graph. The portion $BC$ of the graph represents the conversion of

$A$ block of ice with mass $m$ falls into a lake. After impact,a mass of ice $m/5$ melts. Both the block of ice and the lake have a temperature of $0^{\circ}C$. If $L$ represents the latent heat of fusion,the minimum distance the ice fell before striking the surface is

At $100^{\circ}C,$ the substance that causes the most severe burn is:

When vapour condenses into liquid,

Steam at $100\,^{\circ}C$ is more dangerous than the same mass of water at $100\,^{\circ}C$ because the steam