Maximum density of $H_2O$ is at temperature

The figure shows a glass tube (linear co-efficient of expansion is $\alpha$) completely filled with a liquid of volume expansion co-efficient $\gamma$. On heating length of the liquid column does not change. Choose the correct relation between $\gamma$ and $\alpha$

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

A lead bullet at $27\ ^oC$ just melts when stooped by an obstacle. Assuming that $25\%$ of heat is absorbed by the obstacle, then the velocity of the bullet at the time of striking  ……. $m/s$  ( $M.P.$ of lead $= 327\,^oC$ , specific heat of lead $= 0.03\,cal/g\,^oC$ , latent heat of fusion of lead $= 6\,cal/g$ and $J = 4.2\,joule/cal$ )

The graph $AB$ shown in figure is a plot of temperature of a body in degree Celsius and degree Fahrenheit. Then