Question

The diagram below shows an aquarium with four typical optical devices submerged in some liquid that has a higher index of refraction than the glass. Each optical device is labelled. Which of the optical devices converge light when submerged in this liquid?

(A) The concave mirror and the convex lens.
(B) The convex mirror and the concave lens.
(C) The concave mirror and the concave lens.
(D) The concave mirror and the convex lens.
(D) All of the above optical devices converge light underwater.

Answer 1

Hint : here, we have to study all the optical devices that are mentioned in the above diagram and their properties. So that we can obtain the required answer that which of the following converges the light rays if submerged in the liquid which has a refractive index greater than that of the glass.

Complete Step By Step Answer:
Let us first discuss concave mirrors. It is a converging mirror and it converges light rays. Thus, concave mirrors are one of our answers.
For a concave lens is the diverging lens it diverges the light rays.
Convex mirror is also a diverging mirror, it diverges the light rays.
Convex lens is known as the converging lens since, it converges the light rays and the focal length is given as below:
$\dfrac{1}{f} = \left( {\dfrac{{{\mu _{glass}}}}{{{\mu _{liquid}}}} - 1} \right)\dfrac{2}{R}$
Hence, ${\mu _{glass}} < {\mu _{liquid}}$ and $f$ is positive when $R$ is negative.
The answer is that the concave mirror and convex lens are converging.
The correct answer is option A.

Note :
We observed that the concave mirror is converging and the convex lens is also converging. The light rays passing through both of them converge. When the refractive index of liquid is greater than that of the glass it is given that the focal length is positive and also the focal length is said to be positive when the radius of curvature is negative.