Suppose we mold a hollow piece of plastic into the shape of a double concave lens. The

Question:

Suppose we mold a hollow piece of plastic into the shape of a double concave lens. The "lens" is watertight, and its interior is filled with air. We now place this lens in water and shine a beam of light on it.
(a) Does the lens converge or diverge the beam of light? Explain.
(b) If our hollow lens is double convex instead, does it converge or diverge a beam of light when immersed in water? Explain.