The thermal capacity of a body is $80 \, cal/^{\circ}C$. What is its water equivalent?

$A$ piece of copper of mass $250 \ g$ at $500^{\circ} C$ is put inside a calorimeter of water equivalent $50 \ g$ containing $200 \ g$ of water at $20^{\circ} C$. At thermal equilibrium,the temperature of the mixture is $60^{\circ} C$. The specific heat of copper (in $J / kg \cdot ^{\circ} C$) is approximately: [Specific heat of water $= 4200 \ J / kg \cdot ^{\circ} C$]

$A$ piece of ice (heat capacity $= 2100 \ J \ kg^{-1} \ ^{\circ}C^{-1}$ and latent heat $= 3.36 \times 10^5 \ J \ kg^{-1}$) of mass $m$ grams is at $-5^{\circ}C$ at atmospheric pressure. It is given $420 \ J$ of heat so that the ice starts melting. Finally,when the ice-water mixture is in equilibrium,it is found that $1 \ g$ of ice has melted. Assuming there is no other heat exchange in the process,the value of $m$ is:

$A$ $50 \,g$ ice cube at $-10^{\circ} C$ is added to $200 \,g$ of water at $30^{\circ} C$. The final temperature of the mixture is (specific heat of water $= 1 \,cal \,g^{-1} {}^{\circ} C^{-1}$,latent heat of fusion of ice $= 80 \,cal \,g^{-1}$,specific heat of ice $= 0.5 \,cal \,g^{-1} {}^{\circ} C^{-1}$). (in $^{\circ} C$)

An aluminium piece of mass $50 \,g$ initially at $300^{\circ} C$ is dipped quickly and taken out of $1 \,kg$ of water,initially at $30^{\circ} C$. If the temperature of the aluminium piece immediately after being taken out of the water is found to be $160^{\circ} C$,the temperature of the water is ............ $^{\circ} C$. The specific heat capacities of aluminium and water are $900 \,J \,kg^{-1} K^{-1}$ and $4200 \,J \,kg^{-1} K^{-1}$,respectively.

$A$ sphere of $0.047 \; kg$ aluminium is placed for a sufficient time in a vessel containing boiling water,so that the sphere is at $100 \; ^{\circ}C$. It is then immediately transferred to a $0.14 \; kg$ copper calorimeter containing $0.25 \; kg$ water at $20 \; ^{\circ}C$. The temperature of the water rises and attains a steady state at $23 \; ^{\circ}C$. Calculate the specific heat capacity of aluminium in $kJ \; kg^{-1} K^{-1}$.