Assertion `:` The focal length of the lens does not change when red light is replaced by blue light.
Reason`:` The focal length of lens does not depends on colour of light used.

Options

A. STATEMENT -`1`is true statement `2` is true,Statement -`2`is a correct explanation for statement -`1`
B. STATEMENT -`1`is true statement `2` is true,Statement -`2`is a not a correct explanation for statement -`1`
C. Statement -`1`is true,Statement -`2`is False
D. Statement -`1`is False ,Statement -`2`is True

Answer

D

Explanation

The focal length of a Lens Is given be formula`(1)/(f)=(mu-1)((1)/(R_(1))-(1)/(R_(2)))`
as `mu_(b) gt mu_(R) therefore f_(b) lt f_(r)` therefore focal length o flens decreases when red light is replaced by blue light.