Download Reflection of Light

Reflection of Light
Demo: MIRAGE. Discuss.
Reflection, Refraction, and
Absorption
Air
Reflection: A ray
from air strikes
the water and
returns to the air.
Refraction: A ray
bends into the
water toward the
normal line.
absorption
reflection
Water
refraction
Absorption: A ray is
absorbed atomically
by the water and
does not reappear.
The Laws of Reflection
1. The angle of incidence qi is equal
to the angle of
reflection qr :
Air
N
reflection
qi qr
Water
qi = qr
All ray angles are measured with respect to normal N.
2. The incident ray, the
reflected ray, and
the normal N all lie
in the same plane.
3. The rays are
completely
reversible.
The Plane Mirror
A mirror is a highly polished surface that forms images
by uniformly reflected light (specular reflection).
Note: images
appear to be
equidistant
behind mirror
and are rightleft reversed.
Specular vs. Diffuse Reflection
Would you be able to see this PowerPoint if the
screen produced specular reflection only? Not really.
The reason why you see the movie in a movie
theater is because the screen is not smooth and it
produces a diffuse reflection.
Real and Virtual
Real images and
objects are formed
by actual rays of
light. (Real images
can be projected on
a screen.)
Light rays
Real
object
No light
Virtual
image
Virtual images and
objects do not really Virtual images are on the
exist, but only seem opposite side of the mirror
to be at a location.
from the incoming rays.
Q: How much of the mirror do you need to see all of
yourself in a mirror? A mirror ½ your height.
Image of an Extended Object