$2 \ kg$ of ice at $-20^{\circ} C$ is mixed with $5 \ kg$ of water at $20^{\circ} C$. The final mass of water formed is: (in $kg$)

$5\,g$ of ice at $0\,^{\circ}C$ is dropped in a beaker containing $20\,g$ of water at $40\,^{\circ}C$. The final temperature will be ........ $^{\circ}C$.

Water of volume $2\, L$ in a closed container is heated with a coil of $1\, kW$. While water is heated,the container loses energy at a rate of $160\, J/s$. In how much time will the temperature of water rise from $27\, ^\circ C$ to $77\, ^\circ C$? (Specific heat of water is $4.2\, kJ/kg\cdot K$ and that of the container is negligible)

If an electric heater is rated at $1000\,W$,then the time required to heat one litre of water from $20\,^{\circ}C$ to $60\,^{\circ}C$ is

The temperatures of equal masses of three different liquids $A, B$ and $C$ are $15^{\circ} C, 24^{\circ} C$ and $30^{\circ} C$ respectively. The resultant temperature when liquids $A$ and $B$ are mixed is $20^{\circ} C$ and when liquids $B$ and $C$ are mixed is $26^{\circ} C$. Then the ratio of specific heat capacities of the liquids $A, B$ and $C$ is

If equal masses of $10$ liquids of specific heats $s, 2s, 3s, \ldots, 10s$ at temperatures $10^{\circ} C, 20^{\circ} C, 30^{\circ} C, \ldots, 100^{\circ} C$ respectively are mixed,the resultant temperature of the mixture is . . . . . . . (in $^{\circ} C$)