$2\,g$ of steam condenses when passed through $40\,g$ of water initially at $25\,^oC$. The condensation of steam raises the temperature of water to $54.3\,^oC$, ........ $cal/g$ is the  latent heat of steam ?

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 $J = 4.2\,joule/cal$ )

One kilogram of ice at $0\,^oC$ is mixed with one kilogram of water at $80\,^oC$. Temperature of mixture is ........ $^oC$  (specific heat of water $= 4200\,J\,kg^{-1}\,K^{-1}$ and latent heat of ice $= 336\,KJ \,kg^{-1}$ )

Three rods of equal length $l$  are joined to form an equilateral triangle $PQR.$  $O$  is the mid point of $PQ.$  Distance $OR$  remains same for small change in temperature. Coefficient of linear expansion for $PR$ and $RQ$  is same, $i.e., \alpha _2$  but that for $PQ$  is $\alpha _1.$ Then

Four rods of same material with different radii $r$ and length $l$ are used to connect two reservoirs of heat at different temperatures. Which one will conduct most heat ?

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 ...... $^o$