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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