A coin lies on the bottom of a lake 2 m deep at a horizontal distance x from the spot light S which is a source of thin parallel beam of light situated 1 m above the surface of the liquid of refractive index p= as shown in figure. The liquid height is 2m. Find x so that a narrow beam of light from S when incident on the liquid surface at incidence angle `45^(@)` fells directly on the coin

Answer

`(1+(2)/(sqrt(3)))m`