A thick plane mirror, silvered at its back, forms multiple number of images. Out of these, the brightest image is :
(a) first image
(b) second image
(c) third image
(d) All are of equal brightness

(b) second image

Reason — A thick plane mirror forms a number of images due to multiple reflections within the glass from front surface and back reflecting surface. Out of these, the second image formed due to reflection from the back reflecting surface is the brightest.