Which of the following material is used to make calorimeter?

Thermocouple is an arrange ment of two different metal to :-

$50\, g$ ice at $0\,^oC$ is dropped into a calorimeter containing $100\, g$ water at $30\,^oC$. If thermal capacity of calorimeter is zero then amount of ice left in the mixture at equilibrium is ........ $gm$

Three liquids with masses ${m_1},\,{m_2},\,{m_3}$ are thoroughly mixed. If their specific heats are ${c_1},\,{c_2},\,{c_3}$ and their temperatures ${T_1},\,{T_2},\,{T_3}$ respectively, then the temperature of the mixture is

A piece of ice (heat capacity $=$ $2100$ $J kg^{-1}$ $^o C^{-1}$ and latent heat $=$ $3.36$ $×$ $10^5$ $J kg^{-1}$) of mass $m$ grams is at $-5^o C$ 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 $1$ $gm$ of ice has melted. Assuming there is no other heat exchange in the process, the value of $m$ is ...... $gm$

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