Assertion Internal energy of an ideal gas does not depend on volume of gas.

Reason Internal energy depends only on temperature of gas.

The coefficient of cubical expansion of mercury is $$0.00018 /{ }^{\circ} \mathrm{C}$$ and that of brass $$0.00006 /{ }^{\circ} \mathrm{C}$$. If a barometer having a brass scale were to read $$74.5 \mathrm{~cm}$$ at $$30^{\circ} \mathrm{C}$$, find the true barometric height at $$0^{\circ} \mathrm{C}$$. The scale is supposed to be correct at $$15^{\circ} \mathrm{C}$$.

One mole of an ideal diatomic gas undergoes transition from A to B along a path AB as shown below.

The change in internal energy of the gas during the transition is

Assertion : It is hotter over the top of a fire than at the same distance on the sides.

Reason : In the upward direction, the heat propagate through convection.