If the r.m.s speed of chlorine molecule is 490ms^-1 at 27^oC, the r.m.s speed of argon molecules at the same temperature will be (Atomic mass of…
JEE Main 2023 — Physics Thermodynamics
2023mcqeasy
If the r.m.s speed of chlorine molecule is 490ms−1 at 27oC, the r.m.s speed of argon molecules at the same temperature will be (Atomic mass of argon =39.9u, molecular mass of chlorine =70.9u)
Official previous-year question
Held on 12 Apr 2023 · Verified 6 Jul 2026.
Options
A
551.7ms−1
B
651.7ms−1
C
451.7ms−1
D
751.7ms−1
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Solution
The formula to calculate the rms speed of the argon molecules is given by
vAr=MAr3RT...(1)
The formula to calculate the rms speed of chlorine molecule is given by
vCl=MCl3RT...(2)
Divide equation (1) by equation (2) and simplify to obtain the required ratio.
vClvAr=MArMCl...(3)
Substitute the values of the known parameters into equation (3) and solve to calculate the required value.