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Karnataka Board PUCPUC Science Class 11

A gas mixture consists of molecules of types A, B and C with masses mA > mB > mC. Rank the three types of molecules in decreasing order of average K.E.

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Question

A gas mixture consists of molecules of types A, B and C with masses mA > mB > mC. Rank the three types of molecules in decreasing order of average K.E.

Short/Brief Note
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Solution

The average K.E. will be the same, as conditions of temperature and pressure are the same.

Now as, `v_(rms) = sqrt((3pV)/M) = sqrt((3RT)/M)`

= `sqrt((3RT)/(mN)) = sqrt((3kT)/m)`

Where, M = Molar mass of the gas

m = Mass of each molecular of the gas

R = Gas constant

Clearly, `v_(rms) ∝ sqrt(1/m)`

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Chapter 13: Kinetic Theory - Exercises [Page 94]

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NCERT Exemplar Physics Exemplar [English] Class 11
Chapter 13 Kinetic Theory
Exercises | Q 13.21 (a) | Page 94

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