$250\,gm$ of water and an equal volume of alcohol of mass $200\,gm$ are placed successively in the same calorimeter and cools from $60^{\circ}\,C$ to $55^{\circ}\,C$ in $130\,sec$ and $67 sec$ respectively. If the water equivalent of the calorimeter is $10\,gm$. , then the specific heat of alcohol in cal/gm $cal / gm ^{\circ}\,C$ is

A water heater of power $2000\,W$ is used to heat water. The specific heat capacity of water is $4200\,J\,kg ^{-1}\, K ^{-1}$. The efficiency of heater is $70 \%$. Time required to heat $2\,kg$ of water from $10^{\circ}\,C$ to $60^{\circ}\,C$ is $..........s$. (Assume that the specific heat capacity of water remains constant over the temperature range of the water).

The temperature of equal masses of three different liquids $A, B$ and $C$ are $12°C, 19°C$ and $28°C$ respectively. The temperature when $A$ and $B$ are mixed is $16°C$ and when $B$ and $C$ are mixed is $23°C$. The temperature when $A$ and $C$ are mixed is........ $^oC$

An electric kettle (rated accurately at $2.5\, kW$) is used to heat $3\, kg$ of water from $15\,^oC$ to boiling point. It takes $9.5$ minute. Then, the amount of heat that has been lost is

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

A block of ice with mass $m$ falls into a lake. After impact, a mass of ice $m/5$ melts. Both the block of ice and the lake have a temperature of $^o C$. If $L$ represents the heat of fusion, the minimum distance the ice fell before striking the surface is