Optics

Question 1

Energy of photon

Answer 1

E = hf
h -> planks constant
f -> frequency of light

Question 2

law of reflection

Answer 2

angle of reflection equals angle of incidence

Question 3

refraction angle and speed of light in medium

Answer 3

sinθ₁/sinθ₂ = v₁/v₂

Question 4

index of refrction

Answer 4

n = speed of light in vacuum/speed of light in a medium
n = λ/λ_n

Question 5

snell’s law of refraction

Answer 5

n₁sinθ₁ = n₂sinθ₂

Question 6

critical angle of refraction

Answer 6

sinθ_c = n₂/n₁
at θ_c, beem is entirely reflected at material boundery
n₁ is material from which light source originates

Question 7

real image

Answer 7

light rays pass through and diverge from the image point

Question 8

virtual image

Answer 8

light rays do not pass through image point, only appear to diverge from that point

Question 9

magnification

Answer 9

M = image height/object height

Question 10

mirror equation

Answer 10

1/p + 1/q = 2/R = 1/f

p -> object distance
q -> image distance
R -> radius of curvature
f -> focal point

Question 11

focal point

Answer 11

f = R/2

Question 12

positive object location for mirror (p)

Answer 12

positive when object is real

Question 13

negative object location for mirror (p)

Answer 13

virtual image (behind mirror)

Question 14

positive image location for mirror (q)

Answer 14

image is in front of mirror (real image)

Question 15

negative image location for mirror (q)

Answer 15

image is behind mirror (virtual image)

Question 16

positive image hight h’ for mirror

Answer 16

image is upright

Question 17

negative image height h’ for mirror

Answer 17

image is inverted

Question 18

positice focal length and radius of mirror

Answer 18

mirror is concave

Question 19

negative flocal length and radius of mirror

Answer 19

mirror is convex

Question 20

negative magnification of mirror

Answer 20

image is inverted

Question 21

positive magnification of mirror

Answer 21

image is upright

Question 22

object and image distance for refracting surface

Answer 22

n₁/p + n₂/q = (n₂-n₁)/R

Question 23

positive object location for refracting surface (p)

Answer 23

object is in front of surface (real)

Question 24

negative object location for refracting surface

Answer 24

object is in back of surface (virtual)

Question 25

positive image location for refracting surface (q)

Answer 25

image is in back of surface (real)

Question 26

negative image location for refracting surface

Answer 26

image is in front of surface (virtual)

Question 27

positive R for refracting surface

Answer 27

center of curvature is in back of surface

Question 28

negative R for refracting surface

Answer 28

center of curvature is in front of surface

Question 29

lens makers’ equation

Answer 29

1/f = (n-1)(1/R₁ - 1/R₂)

Question 30

thin lense equation

Answer 30

1/p + 1/q = 1/f

Question 31

positive object location for thin lense (p)

Answer 31

object is in front of lense (real)

Question 32

negative object location for thin lens

Answer 32

object is behind lens (virtual object)

Question 33

positive image location for thin lens (q)

Answer 33

image is behind lens (real)

Question 34

negative image location for thin lens (q)

Answer 34

image is in front of lens (virtual)

Question 35

positive R₁ and R₂ for thin lens

Answer 35

center of curvature is behind lens

Question 36

negative R₁ and R₂ for thin lens

Answer 36

center of curvature is in front of lens

Question 37

positive focal length for thin lens

Answer 37

converging lens ()

Question 38

negative focal length for thin lens

Answer 38

diverging lens )(

Question 39

focal length of combination of thin lenses

Answer 39

1/f = 1/f₁ + 1/f₂

Question 40

conditions for interference

Answer 40

sources must be coherent (in phase) and monochromatic (single wavelength)

Question 41

conditions for constructive interference

Answer 41

δ = dsinθ_bright = mλ (m = 0, ±1, ±2, ±3…)

• δ -> path difference: diifference of distance light from slits travel*
• d-> distance between slits*
• θ_bright -> angle between bright bands*

Question 42

conditions for destructive interference

Answer 42

dsinθ_dark = (m + 1/2)λ

m = (0,±1,±2,±3…)

Question 43

position of bright interference bands using small angle approximation

Answer 43

y_bright = λLm/d

Question 44

position of dark interference bands using small angle approximation

Answer 44

y_dark = (m+1/2)λL/d

Question 45

intentsity for bands in double slit experiment

Answer 45

I = I_maxcos²(πdsinθ/λ)

Question 46

intentsity for bands in double slit experiment using small angle approximation

Answer 46

I = I_maxcos²(πdy/λL)

Question 47

constructive interference in thin films

Answer 47

2nt = (m + 1/2)λ

Question 48

destrictive interference in thin films

Answer 48

2nt = mλ

Question 49

destructive interference in single slit experiment

Answer 49

sinθ_dark = mλ/a

Question 50

rayleigh’s condition

Answer 50

resolution occurs when the central maximum of one image falls on the first minimum of another images.

Question 51

minimum angle for resolution of slit

Answer 51

θ_min = λ/a

a -> width of slit

Question 52

minimum angle for resolution in circular aperture

Answer 52

θ_min = 1.22*λ/D

Question 53

angle of maxima for difraction gratting

Answer 53

dsinθ_bright = mλ

Question 54

Bragg’s law

Answer 54

describes difraction pattern from crystals

constructive interference:

2dsinθ = mλ

Question 55

intensity of light through polarizer

Answer 55

I = I_maxcos²θ

Question 56

Brewster’s law

Answer 56

defines polarizing angle of reflection

refracted beam is not polarized, reflected beam is

n = tanθ_p