Question

Within a glass slab, a double concave air bubble is fprmed. How would the air bubble behave?

Answer 1

cocave bubble will behave as convex lens as medium around bubble is denser

Answer 2

The air bubble would behave as a diverging lens, because refractive index of air is less than refractive index of glass. However, the geometrical shape of the air bubble shall resemble a double convex lens.