NEET UG PHYSICS MCQ: RAY OPTICS

1 Medium

1 of 1

Understanding +4 | -1

{f_v}

and

{f_r}

are the focal lengths of a convex lens for violet and red light respectively and

{F_v}

and

{F_r}

are the focal lengths of a concave lens for violet and red light respectively, then

View answer and explanation

Correct option: B

{f_v} < \,\,{f_R}

and

{F_v} < {F_r}

Option B (

{f_v} < \,{f_R}

and

{F_v} < {F_r}

) is correct because the refractive index is higher for violet light than for red light, leading to shorter focal lengths for convex lenses and shorter (more negative) focal lengths for concave lenses.

More Questions from RAY OPTICS

Practice All Chapter MCQs →

An object 5 cm tall is placed

\mathrm{1}\,\,\mathrm{m}

from a concave spherical mirror which has a radius of curvature of

\mathrm{20}\,\,\,\mathrm{cm}

. The size of the image is Red colour is used for danger signals because A ray of light is incident on the hypotenuse of a right-angled prism after travelling parallel to the base inside the prism. If

\mathrm{\mu }

is the refractive index of the material of the prism, the maximum value of the base angle for which light is totally reflected from the hypotenuse is Statement-A: The minimum distance between an object and its real image formed by a convex lens is

2{f}

.

Statement-B: The distance between an object and its real image is minimum when its magnification is -1. Assertion: We cannot produce a real image by plane or convex mirrors under any circumstances.
Reason: The focal length of a convex mirror is always taken negative. If both the object and image are at infinite distance from a refracting telescope its magnifying power will be equal to