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

Amount of heat required to raise the temperature of a body through $1 ^o C$ is called its

The rods of length $L_1$ and $L_2$ are made of materials whose coefficients of linear expansion are $\alpha _1$ and $\alpha _2$. If the difference between the two lengths is independent of temperatures

$200\, g$ of a solid ball at $20\,^oC$ is dropped in an equal amount of water at $80\,^oC$ . The resulting temperature is $60\,^oC$ . This means that specific heat of solid is

A clock which keeps correct time at $20\,^oC$ has a pendulum rod made of brass. How many seconds will it gain or lose per day when temperature falls to $0\,^oC$ ? $(\alpha = 18\times10^{-6}/^oC)$

A cylindrical metal rod of length $L_0$ is shaped into a ring with a small gap as shown. On heating the system