$A$ metal rod is used as a pendulum. If the room temperature increases by $10^{\circ}C$ and the linear expansion coefficient of the metal is $2 \times 10^{-6} {\circ}C^{-1}$,then the percentage change in the time period of the pendulum is ...... $\%$

$A$ copper ring has a diameter of exactly $25 \, mm$ at its temperature of $0^o C$. An aluminium sphere has a diameter of exactly $25.05 \, mm$ at its temperature of $100^o C$. The sphere is placed on top of the ring and the two are allowed to come to thermal equilibrium,with no heat being lost to the surroundings. The sphere just passes through the ring at the equilibrium temperature. The ratio of the mass of the sphere to the ring is: (Given: $\alpha_{Cu} = 17 \times 10^{-6} /^o C$,$\alpha_{Al} = 2.3 \times 10^{-5} /^o C$,specific heat of $Cu = 0.0923 \, cal/g^o C$,and specific heat of $Al = 0.215 \, cal/g^o C$)

The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are $8 \Omega$ and $10 \Omega$ respectively. After inserting in a hot bath of temperature $400^{\circ} C$,the resistance of the platinum wire is: (in $Omega$)

$A$ calorimeter of mass $0.2 \ kg$ and specific heat $900 \ J/kg \cdot K$ contains $0.5 \ kg$ of a liquid of specific heat $2400 \ J/kg \cdot K$. Its temperature falls from $60^{\circ}C$ to $55^{\circ}C$ in one minute. The rate of cooling is ....... $J/s$.

Which of the following best represents the temperature versus heat supplied graph for water,in the range of $-20^{\circ}C$ to $120^{\circ}C$?

The temperature at which the vapour pressure of a liquid becomes equal to the external (atmospheric) pressure is its