Question

Let A and B the two gases and given: (T_A/T_B) = 4 (M_A/M_B). Where T is the temperature and M is molecular mass. If ѵ_A and ѵ_B are the r.m.s speed, then the ratio (ѵ_A/ѵ_B) will be equal to __________ 

(A) 2 

(B) 4 

(C) 0.5 

(D) 1

Answer 1

The correct option (A) 2

Explanation:

V_rms = √(3RT/M_O) i.e. V_rms = √(T/M_o)

∴ (V_A/V_B) = √{(T_A/T_B) × (M_B/M_A)}

Given:

(T_A/T_B)   = 4 (M_A/M_B) hence (V_A/V_B)

= √{4 × (M_A/M_B) × (M_B/M_A)}

= 2

Hence (V_A/V_B) = 2