Question

Considering normal incidence of ray, the equivalent refractive index of combination of 2 slabs shown in the figure is

a) 1.8
b) 1.43
c) 2
d) None of the above

(the answer is option 2)
Please write the steps and also write all the variables' names.


PS. the refractive index of the upper slab is 4/3 and lower slab is 3/2 (incase the picture isnt clear)

Answer 1

Answer:

Explanation:

=> It is given that,

• the refractive index of the upper slab μ1 = 4/3

• the refractive index of the lower slab μ2 = 3/2

• the thickness of the upper slab t1 = 10cm

• the thickness of the lower slab t2 = 15cm

=> Here, Considering normal incidence of ray, the equivalent refractive index of combination of 2 slabs:

μ = Σti ÷ Σti/μi

μ = t1 + t2 ÷ t1/μi + t2/μ2

μ = 10 + 15 ÷ 10/4/3 + 15/3/2

μ = 25 ÷  10*3/4 + 15*2/3

μ = 25 ÷ 7.5 + 10

μ = 25 ÷ 17.5

μ = 1.43

=> Thus, the equivalent refractive index of combination of 2 slabs is 1.43.