The diagram shows two pieces of wood resting in shallow water of constant depth. Straight, parallel wavefronts approach the pieces of wood as indicated. The gap between the pieces of wood is 2.0 cm wide and the wavefronts are 3.0 cm apart.
What is the appearance of the wavefronts after they pass through the gap?
straight and 2.0 cm apart
semicircular and 2.0 cm apart
straight and 3.0 cm apart
semicircular and 3.0 cm apart