JEE Main · 2022 · 28 Jun 2022 · Shift 2 · Heat & Thermodynamics

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What will be the effect on the root mean square velocity of oxygen molecules if the temperature is doubled and oxygen molecule dissociates into atomic oxygen?

(A)The velocity of atomic oxygen remains same
(B)The velocity of atomic oxygen doubles✓ Correct
(C)The velocity of atomic oxygen becomes half
(D)The velocity of atomic oxygen becomes four times

Answer: (B)

Solution

v_{r m s} = \frac{3 R T}{M}

. When temperature doubles (

T \to 2 T

) and molecular mass halves (

M \to M /2

), the ratio

\frac{T}{M}

increases by a factor of 4. Thus

v_{r m s}

increases by

4 = 2

, i.e., the velocity doubles.

JEE Main · 2022 · 28 Jun 2022 · Shift 2 · Single correct option

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