$A$ block of ice at $-20\,^oC$ having a mass of $2\, kg$ is added to $3\, kg$ of water at $15\,^oC$. Neglecting heat losses and the heat capacity of the container,which of the following is true?

The heat required to convert $8 \ g$ of ice at a temperature of $-20^{\circ}C$ to steam at $100^{\circ}C$ is (Specific heat capacity of ice $= 2100 \ J \ kg^{-1} \ K^{-1}$,specific heat capacity of water $= 4200 \ J \ kg^{-1} \ K^{-1}$,latent heat of fusion of ice $= 336 \times 10^3 \ J \ kg^{-1}$ and latent heat of steam $= 2.268 \times 10^6 \ J \ kg^{-1}$) (in $kJ$)

For a copper-iron $(Cu-Fe)$ couple,the thermo $e.m.f.$ (temperature of cold junction $= 0\,^{\circ}C$) is given by $E = (14\theta - 0.02\theta^2)\,\mu V$. The neutral temperature will be

$A$ block of ice at $0^{\circ}C$ falls from a height of $1 \ km$ onto an insulating surface. If all its kinetic energy is converted into heat,what fraction of the ice will melt? (Take $g = 10 \ m/s^{2}$ and latent heat of fusion of ice $L = 3.36 \times 10^{5} \ J/kg$)

$A$ continuous flow water heater (geyser) has an electrical power rating $= 2 \, kW$ and efficiency of conversion of electrical power into heat $= 80 \%$. If water is flowing through the device at the rate of $100 \, cc/sec$,and the inlet temperature is $10^{\circ} C$,the outlet temperature will be ....... $^{\circ} C$.

An electric heater with a constant heat supply rate is used to convert a certain amount of liquid ammonia to saturated vapour at high pressure. The heater takes $14 \text{ minutes}$ to bring the liquid at $15^{\circ}C$ to the boiling point of $50^{\circ}C$ and $92 \text{ minutes}$ to convert the liquid at the boiling point wholly to vapour. If the specific heat capacity of liquid ammonia is $4.9 \text{ kJ/kg K}$,the latent heat of vaporisation of ammonia in $\text{kJ/kg}$ is: