Question

Which one of the following materials cannot be used to make a lens?
(a) Water
(b) Glass
(c) Plastic (d) Clay
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Answer 1

d) clay.................

Answer 2

Explanation:

Glass and water are transparent materials. There is a certain amount of plastic that is transparent so that the plastic can be used to make a lens, but the clay is an opaque substance so that the light can not be transmitted into it and the clay can not be used to create the lens.