Question

A man places a rectangular glass slab of thickness 9 cm on a newspaper. On the top of the glass slab he places a glass beaker of negligible wall thickness containing water up to a height of 6 cm. If refractive index of glass is 1.5 and refractive index of water is (4/3), what is the apparent depth of the newspaper?

Answer 1

We use,

μ=Real depth/thickness of the objectApparent depth
Due to refraction at two boundaries, the apparent depth of the newspaper will be

Apparent depth=thickness of the glassμglass+thickness of the waterμwater
=91.5+61.3=6+4.6
Apparent depth of the newspaper=10.6 cm