Q 11-12-028JEE MainJEE Main 2026 (6 Apr, Shift 2)Easy
If $2$ mole of an ideal monoatomic gas at temperature $T$, is mixed with $6$ mole of another ideal monoatomic gas at temperature $2T$ then the temperature of mixture is:
Answer: (D) $\dfrac{7}{4}T$
Internal energy is conserved and both gases have the same $C_v$:
$$2T + 6(2T) = 8T_f \;\Rightarrow\; T_f = \frac{14T}{8} = \frac{7}{4}T$$
Solution by Sreeraj P, M.Sc Physics