Question 360: Ray Optics

Question

Two identical concave mirrors each of focal length
f
are facing each other as shown in the schematic diagram. The focal length
f
is much larger than the size of the mirrors. A glass slab of thickness
t
and refractive index
n_0
is kept equidistant from the mirrors and perpendicular to their common principal axis. A monochromatic point light source
S
is embedded at the center of the slab on the principal axis, as shown in the schematic diagram. For the image to be formed on
S
itself, which of the following distances between the two mirrors is/are correct:
![](https://app-content.cdn.examgoal.net/fly/@width/image/jaoe38c1maw5mqm2/989f38da-44f3-454d-aa18-a69451d50577/ac2c69a0-3546-11f0-b729-5fff17d2171c/file-jaoe38c1maw5mqm3.png?format=png)

Accepted Answer

$ \begin{aligned} & \frac{S-t}{2}+\frac{t}{2 n_0}=2 f \ & S+t\left(\frac{1}{n_0}-1ight)=4 f \ & S=4 f+\left(1-\frac{1}{n_0}ight) t \end{aligned} $
Also
$ \begin{aligned} & \frac{S-t}{2}+\frac{t}{2 n_0}=f \ & S=2 f+\left(1-\frac{1}{n_0}ight) t \end{aligned} $
![](https://app-content.cdn.examgoal.net/fly/@width/image/jaoe38c1may0grre/5135ff39-67fc-45d9-8b9d-c21681ef1bb0/09dbcea0-364c-11f0-b4c7-3fd17612738b/file-jaoe38c1may0grrf.png?format=png)

Answer

$4f + \left(1 - \frac{1}{n_0}\right)t$

Answer

$2f + \left(1 - \frac{1}{n_0}\right)t$

Answer

$4f + (n_0 - 1)t$

Answer

$2f + (n_0 - 1)t$

Ray Optics

Choose the correct answer: