Calorie is defined as the amount of heat required to raise temperature of $1g$ of water by $1°C$ and it is defined under which of the following conditions

In an industrial process $10\, kg$ of water per hour is to be heated from $20°C$ to $80°C$. To do this steam at $150°C$ is passed from a boiler into a copper coil immersed in water. The steam condenses in the coil and is returned to the boiler as water at $90°C.$ how many $kg$ of steam is required per hour. $($Specific heat of steam $= 1$ $calorie \,per\, gm°C,$ Latent heat of vaporisation $= 540 \,cal/gm)$

An experiment takes $10\, minutes$ to raise the temperature of water in a container from $0\,^oC$ to $100\,^oC$ and another $55\, minutes$ to convert it totally into steam by a heater supplying heat at a uniform rate . Neglecting the specific heat of the container and taking specific heat of water to be $1\, cal / g\,^oC$, the heat of vapourization according to this experiment will come out to be …….. $cal/g$

A 'thermacole' icebox is a cheap and an efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side $30 \,cm$ has a thickness of $5.0\; cm .$ If $4.0\; kg$ of ice is put in the box, estimate the amount of ice (in $kg$) remaining after $6 \;h$. The outside temperature is $45\,^{\circ} C ,$ and co-efficient of thermal conductivity of thermacole is $0.01\; J s ^{-1} m ^{-1} K ^{-1} .$ Heat of fuston of water $=335 \times 10^{3}\;J kg ^{-1} $

The temperature of equal masses of three different liquids ${x}, {y}$ and ${z}$ are $10^{\circ} {C}, 20^{\circ} {C}$ and $30^{\circ} {C}$ respectively. The temperature of mixture when ${x}$ is mixed with ${y}$ is $16^{\circ} {C}$ and that when ${y}$ is mixed with $z$ is $26^{\circ} {C}$. The temperature of mixture when $x$ and $z$ are mixed will be …… $^{\circ} {C}$