Sound waves travel at 350m/s through a warm air and at 3500 m/s through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air

Options

(a) decreases by a factor 10
(b) increases by a factor 20
(c) decreases by a factor 20
(d) increases by a factor 10

Correct Answer:

decreases by a factor 20

Explanation:

We have, v = nλ ⇒ v ∞ λ (as n remains constant)
Thus, as v increases 10 times, λ also increases 10 times.