Question

A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5° and the prism is made of a material of refractive index 1.5, the angle of incidence is(a) 7.5°(b) 5°(c) 15°(d) 2.5°

Answer 1

(a)is the correct answer

1.5=x/5

1.5×5=x

x=7.5

Answer 2

Answer:

A) 7.5°

Explanation:

Angle of prism = A =5°  (Given)

Refractive index = μ = 1.5  

(Given)

i2 = 0°

r2 = 0°

r1+r2 = A

= r1 = A−r2

= 5−0 = 5°

μ = sini1/sinr1

sini1 = μsinr1

= 1.5 × sin 5°

= 1.5 × 0.087

= 0.1305

= 7.5°

Therefore, the angle of incidence is 7.5°