STANDARDPhysics-Kinetic Theory of Gases

STANDARD Physics Root Mean Square Speed MCQ Question

Type: MCQ-numerical-Medium-Class 11

If three molecules have velocities 0.5 km s⁻¹, 1 km s⁻¹ and 2 km s⁻¹, the ratio of the rms speed and average speed is

A

2.15

B

1.13

C

0.53

D

3.96

Correct Answer

Option B

Detailed Explanation

The rms speed is calculated using the formula v_rms = √((v₁² + v₂² + v₃²)/3), and the average speed is (v₁ + v₂ + v₃)/3. Substituting the given velocities, v_rms = 1.32 km s⁻¹ and average speed = 1.17 km s⁻¹. The ratio is 1.32/1.17 ≈ 1.13.

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