Wave Speed in Shallow Water

Steps:

• Water waves travel faster in deeper water due to less bottom friction and greater depth.
• The speed of shallow water waves is given by v = √(gh), where g is gravity and h is water depth.
• As the wavefront enters shallower water, h decreases.
• Thus, v decreases, slowing the wavefront.

Why B is correct:

• According to the shallow water wave speed formula v = √(gh), speed decreases as depth h decreases.

Why the others are wrong:

• A: Speed decreases, not increases, per the formula.
• C: Wavelength shortens because frequency stays constant while speed drops (λ = v/f).
• D: Wavelength decreases, not increases, due to reduced speed.

Final answer: B