What happens when EM waves
passes through a medium of
different densities?
Refractio
n
the change in direction of a wave
passing from one medium to
another caused by its change in
speed
Direction of the bending of EM
Waves
Towards the
normal
EM waves moving
towards a medium of
higher index of
refraction
Away from the
normal
EM waves moving
towards a medium of
lower index of refraction
the ratio of the sines of the angles of
incidence and refraction of a wave are
constant when it passes between two
given media.
𝑣1
sin 𝑖
=
𝑣2
sin 𝑟
𝑛𝑟
=
𝑛𝑖
𝑅𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑣𝑒 𝐼𝑛𝑑𝑒𝑥 𝑜𝑓 𝑎 𝑚𝑒𝑑𝑖𝑢𝑚
𝑛𝑖 sin 𝑖 = 𝑛𝑟 sin 𝑟
Total Internal Reflection
takes place at the boundary between two
transparent media when a ray of light in a
medium of higher index of refraction
approaches the other medium at an angle
of incidence greater than the critical angle.
Conditions for Total Internal Reflection
1. Is travelling from an optically denser
medium (higher refractive index) to an
optically less dense medium (lower
refractive index)
2. the angle of incidence is greater than
the critical angle.
Applications of Total Internal Reflection
Applications of Total Internal Reflection
Consider glass with index of refraction
n = 1.52. If light propagating within the
glass encounters a glass-air interface,
the critical angle is