Light and Optics

Question 1

Equation: Speed of light in a vacuum

Answer 1

c = wavelength * frequency

Question 2

Wavelength and frequency are ________ proportional. So a _______ wavelength implies a _______ frequency.

Answer 2

inversely
longer wavelength
lower frequency

Question 3

Equation: Index of Refraction

Answer 3

n = c / v

Note: n = angle of refraction; c = speed of light through a vacuum; v = speed of light in material medium

Question 4

The impedance of a medium to the passage of light

Answer 4

index of refraction (n)

Question 5

index of refraction in a vacuum

Answer 5

n = 1

Question 6

speed of light in a material medium

Answer 6

v

Question 7

T/F: v < c and n > 1 for all media except in a vacuum

Answer 7

True

Question 8

as light travels from one medium into another, the frequency does not change but the _______ and the ______ will

Answer 8

wavelength and the speed

Question 9

Law of Reflection

Answer 9

ø incidence = ø reflection

angle of incidence always equals the angle of reflection

Question 10

When drawing a line “Normal” to the surface of a refracting material, always draw the line ______ to the interface. Define the angles from the normal to the ray.

Answer 10

perpendicular

Question 11

Equation: Snell’s Law

Answer 11

n1 * sin(ø1) = n2 * sin(ø2)
Note: n1 and n2 are indices of refraction for the appropriate medium; ø1 and ø2 are the angles between the refracted rays and the “normal”

Question 12

Usually, when light crosses a boundary between two media of different indices of refraction, it is partly _______ and partly ________

Answer 12

reflected and partly refracted

Question 13

When light goes from a medium of high to one of low refractive index, if the angle of incidence is larger than the _________, then all of the light is reflrected

Answer 13

critical angle

Question 14

Formula: Total internal reflection (critical angle)

Answer 14

sin(ø)crit = n2 / n1

Note: n2 < n1

Question 15

If n2 is greater than n1, then the light will bend ________ normal

Answer 15

towards the Normal

Question 16

If n2 is < n1, light bends ________ from normal

Answer 16

away from Normal

Question 17

a concave mirror is _______

Answer 17

converging

Question 18

a concave lens is ________

Answer 18

diverging

Question 19

a convex mirror is ________

Answer 19

diverging

Question 20

convex lens is __________

Answer 20

converging

Question 21

Equation: Focal Length

*(mirrors and lenses)

Answer 21

1/f = 1/do + 1/di

Note: 1 / focal length = 1/object distance + 1/image distance (from the source)

Question 22

d(o) is always _____ for a real object

Answer 22

positive

Question 23

Equation: Magnification

Answer 23

m = -d(i) / d(o)

Question 24

When magification is > 0, it means that the image is _______

Answer 24

upright

Question 25

When magnification is < 0, it means that the image is _______

Answer 25

inverted

Question 26

if the absolute value of magnification |m| > 1, then the image is

Answer 26

an enlarged image

Question 27

if the absolute value of magnification is < 1, then the image is

Answer 27

a reduced image

Question 28

if focal length is positive, then the lens/mirror is _______

Answer 28

converging

Question 29

if the focal length is negative, then the lens/mirror is _______

Answer 29

diverging

Question 30

if the image distance (di) is positive, then it is a ______

Answer 30

real image

Question 31

if the image distance (di) is negative, then it is a ________

Answer 31

virtual image

Question 32

if the object distance (do) is positive, then the object is on the ___________ as light going in

Answer 32

same side

Question 33

if the object distance (do) is negative, then the object is on the ___________ as light going in

Answer 33

opposite side

Question 34

For a positive object distance (object on the same side as light going in), m > 0 means that the image distance has to be _______, which means that it has to be virtual

Answer 34

negative | di is negative for a virtual image

Question 35

______ images are upright (erect)

Answer 35

virtual images

Question 36

For a positive object distance (object on the same side as light going in), when m < 0, the image distance has to be __________, and the image has to be real.

Answer 36

positive | di is positive for a real image

Question 37

_______ images are inverted

Answer 37

Real images