Sound waves travel at 350 ms-1 through a warm air and at 3500 ms-1 through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air

Question

Sound waves travel at 350 ms-1 through a warm air and at 3500 ms-1 through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air (A) decrease by a factor 10 (B) increase by a factor 20 (C) increase by a factor 10 (D) decrease by a factor 20

Tardigrade Admin · Accepted Answer

Velocity of sound v=n λ (v1/v2) =(n1 λ1/n2 λ2) (but n1=n2) λ2 =λ1 (v2/v1)=λ1 × 10 λ2 =10 λ1

Q. Sound waves travel at $350 m s^{- 1}$ through a warm air and at $3500 m s^{- 1}$ through brass. The wavelength of a $700 Hz$ acoustic wave as it enters brass from warm air

decrease by a factor $10$

increase by a factor $20$

increase by a factor $10$

decrease by a factor $20$

Velocity of sound $v = nλ$
$\frac{v _{1}}{v _{2}} = \frac{n _{1} λ _{1}}{n _{2} λ _{2}}$ (but $n_{1} = n_{2}$ )
$λ_{2} = λ_{1} \frac{v _{2}}{v _{1}} = λ_{1} \times 10$
$λ_{2} = 10 λ_{1}$

Q. Sound waves travel at 350ms−1 through a warm air and at 3500ms−1 through brass. The wavelength of a 700Hz acoustic wave as it enters brass from warm air

decrease by a factor 10

increase by a factor 20

increase by a factor 10

decrease by a factor 20