Question

63. Pick the correct answer from the following two statements : (a) A lens has at least one curved surface. (b) A plano-concave lens has two curved surfaces. (1) Only (a) is true (2) Only (b) is true (a) Both (a) and (b) are true (3) (4) Both (a) and (b) are false (a) and (b) రెండూ తప్పులే (a) మరియు (b) రెండూ నిజాలే​

Answer 1

Answer:

1. only a is true

Explanation:

because it is the definition of a lens that it will have atleast one curved surface.

and b. is wrong as Plano concave have a curved as well as plane surface

only Biconcave lens has two curved surfaces.

Answer 2

• From the given two statements a is true.

• As we know that a lens has at least one curved surface.

• But a Plano concave lens has one concave surface and one flat surface.

• The Plano concave lens is an optical lens.

• As we know that the biconcave lens has two curved surfaces.
• So that statement (a) is correct and statement (b) is wrong.