A sound wave from a jackhammer travels through a section of concrete with a fixed frequency. At the concrete's boundary is mud. The diagram below shows the path of the sound wave as it travels from the concrete into the mud.

Question

What happens to the sound wave when it passes from the concrete into the mud?
A.
Its direction and speed remains the same.
B.
Its direction and speed changes.
C.
Its direction changes but speed remains the same.
D.
Its direction remains the same but speed changes.

Answer 1

When a sound wave travels from one medium to another (in this case, from concrete to mud), several factors come into play. Sound travels at different speeds in different materials due to variations in density and elasticity.

In this case, the speed of sound is generally faster in concrete than in mud. When the sound wave moves from concrete (a denser and more elastic medium) to mud (a less dense and less elastic medium), the wave will change speed and also change direction due to refraction.

Therefore, the correct answer is:

B. Its direction and speed changes.