There is small air bubble inside a glass sphere `(mu=1.5)` of radius 10 cm. The bubble is 4.0 cm below the surface and is viewed normally from the outside figure. Find the apparent depth of the bubble

Explanation

The observe will see the image formed due to refraction at the spherical surface when light from the bubble goes from glass to air.
Here `u=-4cm,R=-10cm,mu_(1)=1.5,mu_(2)=1`
`therefore` From formula, `mu_(2)/v-mu_(1)/u=(mu_(2)-mu_(1))/R`, we get
`1/v=0.5/(10cm)-1.5/(4cm)`
or v = -3 cm
`therefore` The bubble will appear 3 cm below the surface.