Question

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

Answer 1

The observer sees the image formed due to refraction at the spherical surface when the light formt he bubble goes from the glass to the air.
Here, `u=-4.0cm, R=-10cm, mu=1.5` and `mu_(2)=1`.
`(1)/(v)+(-1.5)/(-4.0cm)=(1-1.5)/(-10cm)`
`(1)/(v)=(0.5)/(10cm)-(1.5)/(4.0cm)`
`v=-3.0cm` .
Thus, the bublle will appear `3.0 cm` below the surface.