Question

In the figure you are in a system of two vertical parallel mirrors A and B separated by distance d. A grinning gargoyle is perched at point O, a distance 0.2d from mirror A. Each mirror produces a first (least deep) image of the gargoyle. Then each mirror produces a second image with the object being the first image in the opposite mirror. Then each mirror produces a third image with the object being the second image in the opposite mirror, and so on—you might see hundreds of grinning gargoyle images. How deep behind mirror A are the first, second, and third images in mirror A?

Answer 1

Reading that, made my eyes hurt ._.

Answer 2

such long question haha..

Answer 3

Itʻs a tough cookie

Answer 4

In short, it is asking us to figure out the depth of images produced when you stand between two parallel mirrors

Answer 5

This happens when we go to a barber's shop....let me go there and check :P

Answer 6

or stand adjacent to a dressing mirror holding another small mirror opposite the first mirror :)
https://edlear30.files.wordpress.com/2015/08/4601278995_9594a54739.jpg

Answer 7

Looks this problem can be solved using only one physics law :

angle of incidence = angle of reflection

Answer 8

for plane mirrors, i think there is a property like
"the distance between the mirror and the virtual image is the same as the distance between the object and the mirror..."

Answer 9

Yeah, that follows from the reflection law right ?

Answer 10

yep...
so 0.2d, 1.8d, 2.2d ?

Answer 11

Perfect!

Answer 12

yay :)

Answer 13

This problem keeps me thinking everytime I attempt it... its fascinating how the infinite reflections happen and how the infinitely many absorbtions and emissions of photons by the atoms take place...

Answer 14

yep...
virtual images are simply our brains re-tracing lights path and calculating what the object looks like right?

Answer 15

Its an easy stuff...

Answer 16

yeah, the light rays do not actually pass through a virtual image. but each virual image corresponds to a reflection from the mirror, which corresponds to an absorption+emission of the photon...


"infinitely many virual images" implies that there are "infinitely many reflections"

this in turn implies infinitely many absorptions+emissions of the photons...

Answer 17

infinitely many absorptions+emisions makes no sense
so, clearly there is something wrong with above reasoning...

Answer 18

@ganeshie8 I understand how the first image distance will be 0.2d. But then after this why, 1.8d and then 2.2d?

Answer 19

check this @FaiqRaees
https://www.youtube.com/watch?v=ouWcTmLJvjs