Wave Speed in Shallow Water

Steps:

• Water waves travel slower in shallower depths due to interaction with the bottom.
• Wave speed depends on water depth: v = √(g d) for shallow water waves, where d is depth.
• As the wavefront enters shallower water, d decreases.
• Thus, v decreases, confirming the wavefront slows down.

Why B is correct:

• Shallow water wave speed formula v = √(g d) shows speed decreases as depth d decreases.

Why the others are wrong:

• A: Speed decreases, opposite of increases, per the depth-speed relation.
• C: Wavelength decreases (v = f λ, frequency f constant, so λ shrinks with v).
• D: Wavelength decreases, does not increase, due to constant frequency.

Final answer: B