If two balls of the same metal weighing $5\, g$ and $10\, g$ strike a target with the same velocity,and the heat energy developed is used solely for raising their temperature,then the temperature rise will be higher:

$A$ lead bullet of mass $50 \ g$ at a temperature of $30^{\circ}C$ is fired vertically upwards with a speed of $840 \ m/s$. When the bullet returns to the point of departure,it strikes a large block of ice at $0^{\circ}C$. How much ice (in $g$) will melt? (Specific heat of lead is $0.02 \ cal/g^{\circ}C$,latent heat of fusion of ice is $80 \ cal/g$,and assume all energy is used to melt the ice.)

The thermo $e.m.f.$ of a thermocouple varies with the temperature $\theta$ of the hot junction as $E = a\theta + b\theta^2$ in volts,where the ratio $a/b$ is $700\,^{\circ}C$. If the cold junction is kept at $0\,^{\circ}C$,then the neutral temperature is:

$A$ 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 ....... $^{\circ} C$.

$A$ thermocouple produces $40 \, \mu V/K$. The temperatures of the cold and hot junctions are $40 \, ^\circ C$ and $20 \, ^\circ C$ respectively. If $150$ such thermocouples are connected in series,what is the total thermo-emf produced in $mV$?

The height of a waterfall is $50 \ m$. If $g = 9.8 \ m/s^2$, the difference between the temperature at the top and the bottom of the waterfall is: (in $^{\circ} C$)