$A$ student takes $50 \, g$ of wax (specific heat $= 0.6 \, cal/g \cdot ^\circ C$) and heats it until it boils. The graph between temperature and time is shown below. The heat supplied to the wax per minute and the boiling point are respectively:

$A$ bullet of mass $m$ moving with a uniform velocity $v$ stops suddenly after hitting a target. If the whole mass melts,given the specific heat $S$,initial temperature $25^{\circ}C$,melting point $475^{\circ}C$,and latent heat $L$,then $v$ is given by:

In cold countries,water pipes sometimes burst,because

When the pressure on water is increased,the boiling temperature of water as compared to $100^{\circ}C$ will be:

The variation of density of water with temperature is represented by the

$A$ gun fires a lead bullet of temperature $300 \ K$ into a wooden block. The bullet having a melting temperature of $600 \ K$ penetrates into the block and melts down. If the total heat required for the process is $625 \ J$,then the mass of the bullet is . . . . . . grams. (Latent heat of fusion of lead $= 2.5 \times 10^4 \ J \ kg^{-1}$ and specific heat capacity of lead $= 125 \ J \ kg^{-1} K^{-1}$)