Light and Optics

Question 1

Myopia

Answer 1

nearsighted, far is blurry
diverging lens (concave) because retina is too far back and object far away will form in front of the retina

Question 2

Hyperopia

Answer 2

farsighted, near is blurry
converging lens (convex) because retina is located too far forward and the image forms behind the retina

Question 3

upright images

Answer 3

are always virtual

Question 4

real images

Answer 4

are inverted

Question 5

what happens when the object is at the focal length?

Answer 5

no image is formed

Question 6

Diverging lenses and mirrors

Answer 6

at any object distance
are all Small, Upright, and Virtual (SUV)

concave lens
convex mirror

Question 7

Concave lens/mirror; object at infinity

Answer 7

focal length = image

tiny, inverted, real

Question 8

excitation

Answer 8

molecules can absorb the energy of a photon causing an electron to move from the ground state to a higher energy state

Question 9

emission

Answer 9

molecules can release the energy of an absorbed photon and return to a lower state of energy

Question 10

what happens when some energy is lost to heat and light during emission

Answer 10

the emitted photo will have less energy than the absorbed photon and therefore will have a longer wavelength

this is fluorescence

Question 11

fluorescence

Answer 11

when the energy emitted is less than the energy absorbed due to loss of energy through heat

the molecule will end up having a longer wavelength (long = low energy)

Question 12

speed of light

Answer 12

c = 3 x 10^8 m/s

c= wavelength x frequency

Question 13

electromagnetic waves

Answer 13

transverse waves that propagate through vacuum plus other mediums (air, water)

Question 14

color scheme

Answer 14

smallest waves –> longest waves

gamma, xray, UV, VIBGYOR, IR, microwave, radiowave

Question 15

energy of EM waves

Answer 15

E = hf = hc/wavelength

Question 16

What changes when moving through a new medium?

Answer 16

wavelength and speed of light changes

frequency stays the same

Question 17

How to remember when something is virtual or real image?

Answer 17

When the image is produced in front of something you will need to push it forwards to get it to hit the retina (myopia –> diverging lens) = virtual

When the image is in back of something you will need to move it backwards to hit the retina (hyperopia –> converging lens) = real

Real people come back for their friends, virtual friends will move on

Question 18

dispersion

Answer 18

the separation of light into colors

lower frequency (red) has a lower index of refraction

higher frequency (violet) has a higher index of refraction

Question 19

chromatic aberration

Answer 19

formation of blurry objects due to the effects of dispersion through a lens

objects that are clear in one frequency (red) will become blurry if changes frequency to violet because violet has a larger dispersion than red does

Question 20

spherical aberration

Answer 20

no unique focus point because there is more refraction than predicted

will affect all frequencies equally

Question 21

Snell’s Law

Answer 21

n1sin(theta) = n2sin(theta)

Question 22

How does light refract when the index of refraction is higher in the second medium?

Answer 22

Will turn towards the normal because will move slower

Question 23

How does the light refract when the index of refraction is lower in the second medium?

Answer 23

the light will bend away from the medium because it can travel faster

Question 24

What the equation for the index of refraction

Answer 24

c/v

speed of light in a vacuum/speed of light in a medium

c= 3 x 10^8 m/s

Question 25

refraction

Answer 25

bending of light rays when light crosses at an angle from one medium to another with a different index of refraction

Question 26

lens strength

Answer 26

the measure of a lens’s refractive power

the greater the lens strength, the more light will bend

this is inversely related to the focal length which is the distance of the object to the created image

Question 27

thin lens equation

Answer 27

S = 1/o + 1/i OR 1/f = 1/o+ 1/i

S= strength of lens
F = focal length
o = object distance
i=image distance

S is measured in dipoters (D) which is equal to inverse meters

Question 28

How is the thin lens equation used differently for converging vs diverging lenses?

Answer 28

converging lens has a positive f and i

diverging lens has a negative f and i

Question 29

magnification

Answer 29

height (image)/height(object) = -distance (image)/distance(object)

Question 30

Thin film interference

Answer 30

multicolored arrays generated by reflection events that occur within a system composed of 2 layers of semitransparent media

intensity of light depends on constructive and destructive interference among waveforms of polychromatic light

some light travels through medium one and then is reflected, some light hits medium one and is reflected

this is influenced by thickness - some wavelengths can’t pass through and cause interference if too thick

surface tension and other effects can also cause multicolored arrays

Question 31

diffraction

Answer 31

bending of light around physical corners or very narrow gaps

think of the slit experiment and how light becomes semi circular

Question 32

reflection

Answer 32

once light is past the critical angle (90 degrees) everything will be reflected back onto the same surface