$50\,g$ of copper is heated to increase is temperature by $10\,^oC$. If the same quantity of heat is given to $10\,g$ of water, the rise in its temperature is ........ $^oC$ (Specific heat of copper $= 420\,J-kg^{-1}\,^oC^{-1}$ )
$5$
$6$
$7$
$8$
The portion $AB$ of the indicator diagram representing the state of matter denotes
$200\, g$ 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
Two rods, one made of aluminium and the other made of steel, having initial lengths $l_1$ and $l_2$ respectively are connected together to form a single rod of length $(l_1 + l_2)$. The coefficients of linear expansion for aluminium and steel of $\alpha_1$ and $\alpha_2$ respectively. If the length of each rod increases by the same amount when their temperature is raised by $t^oC$, then the ratio $l_1/(l_1 + l_2)$ :-
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
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 $J = 4.2\,joule/cal$ )