When monochromatic red light is used instead of blue light in a convex lens, its focal length will :

Question

When monochromatic red light is used instead of blue light in a convex lens, its focal length will : (A) increase (B) decrease (C) remain same (D) does not depend on colour of light

Tardigrade Admin · Accepted Answer

μR < μB (1/f) = (μ-1) ((1/R1)-(1/R2)) (1/fB) > (1/fR) fR > fB.

Q. When monochromatic red light is used instead of blue light in a convex lens, its focal length will :

increase

decrease

remain same

does not depend on colour of light

$μ_{R} < μ_{B}$
$\frac{1}{f} = (μ - 1) (\frac{1}{R _{1}} - \frac{1}{R _{2}})$
$\frac{1}{f _{B}} > \frac{1}{f _{R}}$
$f_{R} > f_{B} .$

Q. When monochromatic red light is used instead of blue light in a convex lens, its focal length will :

increase

decrease

remain same

does not depend on colour of light

μR​<μB​ f1​=(μ−1)(R1​1​−R2​1​) fB​1​>fR​1​ fR​>fB​.

$μ_{R} < μ_{B}$
$\frac{1}{f} = (μ - 1) (\frac{1}{R _{1}} - \frac{1}{R _{2}})$
$\frac{1}{f _{B}} > \frac{1}{f _{R}}$
$f_{R} > f_{B} .$