JEE Mains Model Paper 8

OOI ⊥er PA
∠AQP = 90° (ray retraces its path)

∠APQ = 45°
For ∠APQ to be 45°, incident ray should make angle of incidence greater than 45° and less than 90° . (1)
(sin i) = μ sin r
= μ sin 45° = μ / √2
For i 45°,

1

√2

=

µ

√2

or µ = 1.0
For i 90°1 =

µ

√2

or µ = √2
Range is, √2 > μ > 1