Light Flashcards
snells law
n1sinθ1 = n2sinθ2
n is the index of refraction which is dependent upon medium
Ratio of n1 to n2 is =
sinθ2/sinθ1
*Helpful in predicting the direction of refraction when manipulating the medium type
Calculating index of refraction (n)
n = c/v
speed of light in vacuum (3.0 x 10^8) / speed of light in certain medium
True or false:
The index of refraction affects the speed of light traveling through the medium.
True. Speed of light in a medium (v) is inversely proportional to index of refraction of that medium.
True or false:
For smooth surfaces such as a mirror, the angle of reflection is equal to the angle of incidence.
True; θi = θr
Define refraction
The bending of light that takes place as light travels at an angle passing from 1 medium to the next
Total internal reflection
Occurs when light leaving a medium w/ a higher refractive index enters a medium w/ lower refractive index. AND when
θincidence = θreflection
θincendence > θcritical angle
If the refractive indexes of two mediums are equal, is light refracted?
No, light isn’t refracted.
Comparing reflected angle vs. refracted angle on diagram
What is the θrefraction if θincidence = θcritical?
θrefraction is 90˚
This is the max refraction you can have.
Basically when the refractive angle is exactly 90, the incidence angle becomes the critical angle (the angle at which you get the max refraction).
EQUATION for frequency
f = c/λ
Equation for energy of light
E = hf
h is Planck’s constant
Relationship between speed of light and refractive index of medium
Higher refractive index –> slower speed of light
When light travels from a medium w/ higher “n” to a medium with lower “n”, light bends (away/towards) the normal.
away
When light travels from a medium w/ lower “n” to a medium with higher “n”, light bends (away/towards) the normal.
towards
General pattern for refraction comparing n and θ.
If n1 > n2, then θ2 > θ1
and viceversa
Electromagnetic radiation (light) is a (transverse/longitudinal) wave.
Transverse
Electromagnetic spectrum
For a sound wave intensity is directly proportional to amplitude ^2 and energy of the wave.
For light, intensity is directly proportional to what?
The total energy of light emitted and the number of photons emitted from the surface per unit time (causing a more bright spot).
INTENSITY IS NOT RELATED TO THE FREQUENCY OF EACH PHOTON.
Real image vs. virtual image
Real - i is positive; image is in front of the mirror
Virtual - i is negative; image is behind the mirror
If light is completely reflected, incident angle > critical angle; does light travel through only 1 medium or two mediums during total reflection?
Only 1 medium because the light is reflected onto the same medium it came from.
What is the critical angle?
It is the incident angle when the refracted angle = 90˚.
Question: What is the index of refraction of an unknown medium?
Compare the structures of a convex lens vs. concave lens
Convex - center of lens is thicker than edges
Concave - edges thicker than center
How does light pass through a convex lens?
Parallel rays of light passing through lens are bent towards each other into a single focal pt. behind the lens