Assertion (A) The zeroth law of thermodynamics leads to the concept of temperature.

Reason (R) The zeroth law states that two systems in thermal equilibrium with a third system are in thermal equilibrium with each other.

The correct option among the following is

When a gas expands adiabatically, its volume is doubled while its absolute temperature is decreased by a factor of 2 . The value of the adiabatic constant is

An amount of 700 J of heat is transferred to a diatomic gas allowing it to expand with the pressure held constant. The work done on the gas is

176 g of $\mathrm{CO}_2$ can change its temperature from $0^{\circ} \mathrm{C}$ to $30^{\circ} \mathrm{C}$ by absorbing 3600 J of thermal energy. Molar specific heat of $\mathrm{CO}_2\left(\right.$ in $\left.\mathrm{J} \mathrm{mol}^{-1} \mathrm{~K}^{-1}\right)$ is