Optics Question 78

Question: A point source of light B is placed at a distance L in front of the centre of a mirror of width d hung vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror at a distance 2L from it as shown. The greatest distance over which he can see the image of the light source in the mirror is

[IIT-JEE (Screening) 2000]

Options:

A) d/2

B) d

C) 2d

D) 3d

Show Answer

Answer:

Correct Answer: D

Solution:

According to the following ray diagram HI=AB=d

and DS=CD=d2

AH=2AD

GH=2CD=2d2=d

Similarly IJ=d so GJ=GH+HI+IJ

=d+d+d=3d



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