Question

A rectangular block of glass is placed on a printed page

Answer 1

Answer:

Light will no merge from the vertical angle BC as shown in figure

Where

sin i > sinθc (θc = 1/μ)

According to the snell's law at point O

sinθ = μ sin (90°-i)

      = μ cos i

cos i = sinθ/μ

and sin i = √1-cos²i

 = √1 - sin²θ/μ²

Moreover, the condition with no light emerge BC is

√1 - sin²θ/μ² > 1/μ

μ² = 1+sin²θ

So μ² = √2

Therefore the refractive index of a glass  is √2