Optics: refraction of light Flat and curved surfaces

when light enters a new medium

it refracts!

it bends

the amount and direction of refraction depends on

the index of the medium that the light starts in

the index of the medium that the light is entering

the angle that the light enters the new medium

amount and direction that the light refracts is quantified by

Snell's Law

Snell's law

n1sinθ1 = n2sinθ2

angles are respect to the

NORMAL

Not the surface

Light traveling from a lower index medium to a higher index medium (n2>n1) (like air to water) will bend

toward the normal

Light traveling from higher index medium to a lower index medium (n2< n1) such as from water to air, will bend

away from normal

When light hits perpendicular to the surface, it travels

straight without bending

both angle of incidence and angle of refraction are 0

Concept of "apparent depth"

the image of the object appears higher/closer than it actual is

for light traveling from higher index to lower index,

as the angle of incidence increases

the angle of refraction increases

for greater angles of incidences , the beam entering the water gets higher and higher

critical angle

angle of incidence for which the angle of refraction is 90 degrees

An angle of refraction of 90 degrees means that

the light travels along the surface of the second medium and never enters that second medium

the critical angle gives us

total internal reflection

total internal reflection

light travels along the surface of the second medium and never enters that second medium

light is interally reflected in the first medium and is "trapped" in that first medium

any angle of incidence at the surface that is equal to or greater than the critical angle will results in

internal reflection

why do diamonds sparkle

the light headed out of the diamond will exceed the critical angle and be internally reflected

Single Spherical Refractive Surface SSRS

a curved surface

Light traveling from lower index into higher index will bend ______ normal and will result in _____ light in an SSRS

converging

light traveling from a high index to a low index will bend _____ from normal and will _____

away

diverge

Convex SSRS

converging

vergence will be more plus than when it entered

Concave SSRS

diverging

vergence will be more minus than when it entered

U + D = V

Vergence of the light entering the SSRS (U) + Power of the SSRS (D) = Vergence of the light exiting the SSRS (V)

Convex SSRS

Has plus power (D is a plus number)

adds plus power to incoming vergence

exiting light is more plus than entering light

exiting light is more convergent than entering light

lower --> high index

Concave SSRS

Mins power ( D is a minus number)

adds minus power to the incoming vergence

exiting light is more minus than entering

exiting light is more divergent than entering

higher --> lower

An SSRS is NOT exactly considered

a lens

Calculating SSRS Power

D = (n2 - n1) / r

D = power of SSRS

n2 into

n1 from

r = radius of curvature of the SSRS

A convex SSRS has the ___ index bulging into the ___ index.

high index

lower

A concave SSRS has the ___ index bulging into the ___ index.

lower

higher

do flat surfaces change the vergence of light

NO

looking through a window is clear

The flat surface has _____ power

no

radius is infinetly long