MHT CET202617 April 2026Morning ShiftPhysicsKinetic Theory of GasesActual
The speeds of the seven molecules are 1, 3, 5, 7, 2, 4 and 6 km/s respectively. The ratio of their r.m.s. velocity and average velocity will be
Options
- A2 5 : 1
- B5 : 1
- C1 : 2 5
- D5 : 2
Correct answer
D. 5 : 2
Step-by-step solution
The average velocity is given by: v_ avg = 1 + 2 + 3 + 4 + 5 + 6 + 7 7 = 28 7 = 4 km/s The root mean square (r.m.s.) velocity is given by: v_ rms = 1^2 + 2^2 + 3^2 + 4^2 + 5^2 + 6^2 + 7^2 7 v_ rms = 140 7 = 20 = 2 5 km/s The ratio of r.m.s. velocity to average velocity is: v_ rms v_ avg = 2 5 4 = 5 2 Answer: 5 : 2