One quality of a thermometer is that its heat capacity should be small. If $P$ is a mercury thermometer,$Q$ is a resistance thermometer,and $R$ is a thermocouple type,then:

$A$ pendulum clock (fitted with a small heavy bob that is connected with a metal rod) is $5 \ s$ fast each day at a temperature of $15 \ ^oC$ and $10 \ s$ slow at a temperature of $30 \ ^oC$. The temperature at which it is designed to give correct time is ........ $^oC$.

$A$ lead bullet of $20 \ g$ travelling at $300 \ m/s$ strikes against a block of wood and comes to rest. Assuming $50 \%$ of heat is absorbed by the bullet,the increase in its temperature is $.....^{\circ} C$ (take specific heat of lead $= 150 \ J/kg \cdot K$).

Match the following :

Column-$I$	Column-$II$
$(a)$ Combined existence of liquid-gaseous state of substance.	$(i)$ Sublimation curve
$(b)$ Combined existence of solid-gaseous state of substance.	$(ii)$ Fusion curve
	$(iii)$ Vaporization curve

$A$ waterfall is $84 \ m$ high. If half of the potential energy of the falling water gets converted to heat,the rise in temperature of the water will be: (in $^\circ C$)

An aluminium container of mass $100 \, g$ contains $200 \, g$ of ice at $-20^{\circ} C$. Heat is added to the system at the rate of $100 \, cal/s$. The temperature of the system after $4$ minutes will be ....... $^{\circ} C$ (specific heat of ice $= 0.5 \, cal/g^{\circ} C$,latent heat of fusion $L = 80 \, cal/g$,specific heat of $Al = 0.2 \, cal/g^{\circ} C$,specific heat of water $= 1 \, cal/g^{\circ} C$)