JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · States of Matter

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If the distribution of molecular speeds of a gas is as per the figure shown below, then the ratio of the most probable, the average and the roots mean square speeds, respectively, is

(A)1 : 1 : 1
(B)1 : 1 : 1.224✓ Correct
(C)1 : 1.128 : 1.224
(D)1 : 1.128 : 1

Answer: (B)

Solution

The graph represents a symmetrical distribution of molecular speeds. In such a distribution, the most probable speed and the average speed are equal. However, the root mean square speed is always greater than the average speed for any molecular speed distribution. Therefore, the ratio is 1 : 1 : 1.224, where the most probable and average speeds are equal, and the rms speed is 1.224 times these values.

JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · Single correct option

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