Due to cold weather a $1\, {m}$ water pipe of cross-sectional area $1\, {cm}^{2}$ is filled with ice at $-10^{\circ} {C}$. Resistive heating is used to melt the ice. Current of $0.5\, {A}$ is passed through $4\, {k} \Omega$ resistance. Assuming that all the heat produced is used for melting, what is the minimum time required ? (In ${s}$)

(Given latent heat of fusion for water/ice $=3.33 \times 10^{5}\, {J} {kg}^{-1}$, specific heat of ice $=2 \times 10^{3}\, {J}$ ${kg}^{-1}$ and density of ice $=10^{3}\, {kg} / {m}^{3}$

Find the quantity of heat required to convert $40\; gm$ of ice at $-20^{\circ} C$ into water at $20^{\circ} C$. Given $L _{\text {ice }}$ $=0.336 \times 10^6 J / kg$.

specific heat of ice $=2100 \;J / kg - K$ sp heat of water= $4200\; J / kg - K$

When $0.15\; kg$ of $1 ce$ at $0^{\circ} C$ is mixed with $0.30 \;kg$ of water at $50^{\circ} C$ in a container, the resulting temperature is $6.7^{\circ} C$. Calculate the heat of fuston of ice. $(s_{\text {water }}=4186 J kg ^{-1} K ^{-1}$ ).

Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature $T_0$, while Box contains one mole of helium at temperature $(7/3)$ $T_0$ The boxes are then put into thermal contact with each other, and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes). Then, the final temperature of the gases,$T_f$  in terms of $T_0$ is

$0.1\,m^3$ of water at $80\,^oC$ is mixed with $0.3\,m^3$ of water at $60\,^oC$. The final temperature of the mixture is ........ $^oC$

We have half a bucket $(6l)$ of water at $20\,^oC$  . If we want water at $40\,^oC$, how much steam at $100\,^oC$ should be added to it ?