Question

In a tank a 4 cm thick layer of water (μ = 4/3) floats on a 6 cm thick layer of an organic liquid (μ = 1.48) Viewing at normal incidence ,how far below the water surface does the bottom of tank appear to be?

Answer 1

for any liquid ,
                          real depth/apparent depth = μ
                  apparent depth = real depth(l) - shifting(dl)
           so shifting = l(1-(1/μ))
   now for water layer l = 4cm and μ = 4/3
so shifting caused by  water = 4(1-(3/4)) cm = 1 cm
   for organic liquid, l = 6cm and μ = 1.48
so shifting caused by organic liquid = 6(1-(100/148)) = 1.95 cm = 2 cm (approx)
 so total shifting = 1+ 2 = 3 cm
now apparent depth = (4+6) - 3 =7 cm
so the bottom of tank appear to be   7cm below the water surface