A laser beam in water ( ) strikes the flat water–air surface at an angle of measured…
PHYSICS · Single correct · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A laser beam in water (n=1.33) strikes the flat water–air surface at an angle of 48∘ measured from the normal. Which statement correctly describes what happens at the boundary?
(a) Total internal reflection occurs because the incident angle is greater than the critical angle.
(b) The beam refracts into the air because the incident angle is less than the critical angle.
(c) Total internal reflection occurs because light is moving into a medium of higher index.
(d) The beam refracts into the air but bends toward the normal, since refraction always bends toward the normal.