A centigrade and a Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers $140°F$. What is the fall in temperature as registered by the Centigrade thermometer ...... $^o$

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 $J = 4.2\,joule/cal$ )

A cylindrical rod with one end in a steam chamber and the outer end in ice results in melting of $0.1 \,\,gm$ of ice per second. If the rod is replaced by another with half the length and double the radius of the first and if the thermal conductivity of material of second rod is $1/4$ that of first, the rate at which ice melts is $gm/sec$ will be

$540\, g$ of ice at $0\,^oC$ is mixed with $540\, g$ water at $80\,^oC$ . The final temperature of the mixture is

On heating a liquid of coefficient of cubical expansion $\gamma $ in a container having coefficient of linear expansion $\gamma /3,$ the level of liquid in the container will

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