Question

Which of the following material cannot be used to make a lens.
A) Water
B) Glass
C) Plastic
D) Clay

Answer 1

Hint: The material which can be used for a lens should allow light to pass through it. So a material which is opaque will not allow light to pass through it. Opacity can be defined as the measure of the impenetrability of electromagnetic waves, especially light in a material.

Complete step by step answer:
We can see from the options that glass is a substance that is very commonly used to make lenses so it cannot be the answer to the question.
Coming to water, water allows light to pass through it but has a lower refractive index than glass and as it is a fluid it will be difficult to make a lens out of it. But still, it can be used to make a lens.
Coming to plastic, it is a translucent object which doesn’t fully transmit light falling on it. But still, some light can transmit through these objects and the rest of the light is reflected. Plastic is not an ideal option for a lens, but it can act like one since it allows some light to pass through it.
Coming to the last option which is clay, it is opaque which means it does not allow light to pass through it. So clay can never be used to make a lens.
So the answer to the question is option (D)-Clay.

Note: Transparent Objects or materials are materials which do not allow light to reflect off them and transmits most of the light falling on it with some absorption.
Translucent objects allow some of the light to pass through while opaque objects do not allow light to pass through them, most of the light is absorbed and some reflected.