The difference in length between two rods A and B is 60 cm at all temperatures. If $\alpha_{\mathrm{A}}=18 \times 10^{-6} /{ }^{\circ} \mathrm{C}$ and $\alpha_{\mathrm{B}}=27 \times 10^{-6} /{ }^{\circ} \mathrm{C}$, then the length of $\operatorname{rod} \mathrm{A}$ and $\operatorname{rod} \mathrm{B}$ at $0^{\circ} \mathrm{C}$ is respectively

A sample of an ideal gas $\left(\gamma=\frac{5}{3}\right)$ is heated at constant pressure. If 100 J of heat is supplied to the gas, the work done by the gas is

A balloon is filled at $27^{\circ} \mathrm{C}$ and 1 atmospheric pressure by volume $500 \mathrm{~m}^3$ helium gas. At $-3^{\circ} \mathrm{C}$ and 0.5 atmospheric pressure, the volume of helium gas will be