Question

a ray of light incident on an equilateral glass prism of refractive index√3 moves parallel to base of prism inside it.find angle of incidence for this ray?????

Answer 1

∠A=∠B=∠C=60° [since it is equilateral glass prism]

DE parallel to BC

therefore,

∠ADE=60°

∠D+ angle of refraction=90°

therefore, angle of refraction=90-60

                                                =30°

by using snell's law,

refractive index=sini/sinr

√3=sini/sin30

⇒sini=√3/2

⇒ i= sin⁻¹[√3/2]

therefore,

∠i=60°

ie., angle of incidence is 60°