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

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?

TestHub · Accepted Answer

Account for the apparent optical path through the central slab.

A 4f round-trip condition gives the first valid separation.

A 2f return condition gives the second valid separation.

$D = 4 f + (1 - \frac{1}{n _{0}}) t$

or

$D = 2 f + (1 - \frac{1}{n _{0}}) t$

Hence A and B.

Physics - Geometrical Optics Question with Solution | TestHub

Options:(select one or more)

Doubts & Discussion