A point luminous object (O) is at a distance `h` from front face of a glass slab of width d and of refractive index `mu`. On the back face of slab is a reflecting plane mirror. An observer sees the image of object in mirror as shown in figure. Distance of image from front face as seen by observer will be

Options

A. `h+ (2d)/(mu)`
B. `2 h + 2d`
C. `h+d`
D. `h+ (d)/(mu)`

Answer

A

Explanation

As shown in figure glass slab with form the image of bottom i.e., mirror `MM'` at depth `(d/mu)` from its front face. So the distance of object O from virtual mirror `mm'` will be `h + (d/mu)`
Now as a plane mirror forms image behind the mirror at the same distance as the object is in fornt of it, the distance of image I form `mm'` will be `h + (d/u)` and as the distance of vir tual mirror from the front face as seen by observer `=[h+(d)/(mu)] + (d)/(mu) = h + (2d)/(mu)`