Question

As a sound wave travels from liquid water into ice, its wavelength would
A) decrease due to wave speed decreasing as it passes through the ice.
B) increase because the wave speed and frequency have increased.
C) decrease since the frequency is now lower.
D) increase in order to keep the frequency the same due to the increase in speed.

Answer 1

Letter D. Increase in order to keep the frequency the same due to the increase in speed. It is already a property of a wave to change its wavelength to adapt in different forms of fluids.

Answer 2

Answer:

D) increase in order to keep the frequency the same due to the increase in speed.

Explanation:

First of all, we need to understand what happens to the speed of the sound wave as it passes from liquid water to ice.

Sound travels faster in solids than in liquids, because in solids molecules are more packed together, so they are closer, therefore collisions between molecules can be transmitted faster (and a sound wave is given by the collisions between the molecules, which transmit the vibration through matter). Therefore, as it passes from liquid water to ice, the speed of the sound wave increases.

The frequency of the wave, however, does not change. We can see what happens to the wavelength by looking at the equation:

$v= f \lambda$

where v is the speed of the wave, f is the frequency and $\lambda$ the wavelength. Since the speed v increases and f remains the same, $\lambda$ must increase, so the wavelength of the sound wave as it passes from liquid water to ice increases.