Question

A drop of water behaves like a _____ lens.

Answer 1

Hint: Here are two types of lenses, converging and diverging lenses. So, first we will understand the properties of converging and diverging lenses and then based on that we will find which properties match the properties of an air bubble and then we will find the answer.

Complete step by step solution:
In the given question we are asked how a drop of water behaves but before finding it, we will understand the type of lenses. So, there are two types of lenses converging and diverging lens, they can be defined as,
Converging lens: a convex lens in which light rays that enter it parallel to its axis converge at a single point on the opposite side.

Diverging Lens: A lens that causes the light rays to bend away from its axis is called a diverging lens.

Now, the rays of light converge when they pass through the drops of water. Thus, the drop of water behaves like a convex lens.
Explanation-
A water drop in the air has a higher refractive index as compared to air. And because of its convex shape, it tends to converge a parallel beam of light falling onto it, and therefore it acts as a converging lens. A convex lens is a converging lens. When parallel rays of light pass through a convex lens, the refracted rays converge at one point called the principal focus.

Note:
Do not get confused between converging lens as concave lens and diverging lens as convex lens so read very carefully and remember Whatever the mix of surfaces, if the lens is thicker at its center than its edges it is called a converging lens (having positive focal length). If it is thinner at its center than its edges it is called diverging (having negative focal length).