(a)[1]
In terms of thermal energy, what does it mean for two objects to be in thermal equilibrium?
(b(i))[3]
Show that the gas in X has a temperature of $234^{\circ}\text{C}$.
(b(ii))[3]
Find the number $N$ of molecules in the gas in Y. Explain your answer.
(b(iii))[3]
Explain how the r.m.s. speed of the molecules in X compares with the r.m.s. speed of the molecules in Y.
(iii)[3]
The gas in X is made of molecules, each with a mass four times that of a molecule of the gas in Y. Explain how the r.m.s. speed of the molecules in X compares with the r.m.s. speed of the molecules in Y.