A double convex lens made out of glass (refractive index ${\rm{\mu }} = 1.5)$ has both radii of curvature of magnitudes ${\rm{20 cm}}$. Incident light rays parallel to the axis of this lens will converge at a distance $d$ such that

$d = \frac{{20}}{3}\,\,{\rm{cm}}$

NEET UG PHYSICS MCQ: RAY OPTICS

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A double convex lens made out of glass (refractive index

\mathrm{\mu } = 1.5)

has both radii of curvature of magnitudes

\mathrm{20 cm}

. Incident light rays parallel to the axis of this lens will converge at a distance

d

such that

View answer and explanation

Correct option: D

d = 20\,\,\mathrm{cm}

Option D is correct because using the lens maker's formula, the focal length of the double convex lens is calculated to be 20 cm, which is the distance at which parallel rays converge.

More Questions from RAY OPTICS

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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