Consider the situatuion shown in figure. A plane mirror is fixed at a height h above the bottom of a beaker containing water (refractive index μ ) up to a height d. Find the position of the image of the bottom formed by the mirror.
h−d+dμ.
The bottom of the beaker appears to be shifted up by a distance
△t=(1−1μ)d.
Thus, the apparent distance of the bottom from the mirror is h−△t=h−(1−1μ)d=h−d+dμ. The image is formed behind the mirror at a distance h−d+dμ.