Some water is filled in a container of height 30 cm . If is is to appear half filled to the observer when viewed from the top of the container, the height upto which water should be filled in it, is [Refractive index of water = 4 3 ]

Step-by-step solution

Refractive index of a medium is given by, n= Real depth/ Apparent depth...(i) Given that, height of container =30 ~cm Apparent depth =15 ~cm ...(ii) Real depth = n Apparent depth [ From (i) ] Given that, n_w= 4 3 ...(iii) ...(iii) Real depth =20 ~cm ...[From (ii) and (iii)] x=20 ~cm