Rankers Physics

Sound Wave and its Characteristics: Practice Problem & Solution

Sound waves travel at $350text{ m/s}$ through a warm air and at $3500text{ m/s}$ through brass. The wavelength of a $700text{ Hz}$ acoustic wave as it enters brass from warm air: (2011 Pre)
Decreases by a factor 10
Increases by a factor 20
Increases by a factor 10
Decreases by a factor 20

Solution Explained:

To solve this problem, we apply the core principles of Sound Wave and its Characteristics. Understanding the underlying formula is key to arriving at the correct answer below:

Frequency $f$ remains constant when a wave changes medium. Velocity is given by $v = f\lambda$, which means $\lambda \propto v$. The ratio of velocities is $v_{brass}/v_{air} = 3500/350 = 10$. Thus, the wavelength increases by a factor of 10.

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