Ch. 8: Light and Optics

Question 1

electromagnetic waves

Answer 1

electric field and magnetic field vectors that oscillate perpendicular to each other and propagate as transverse waves

Question 2

electromagnetic spectrum from low frequency/high wavelength to high frequency/low wavelength

Answer 2

radio –> AM –> FM –> Microwaves –> IR –> visible light –> UV –> x-rays –> gamma rays

Question 3

speed of light

Answer 3

speed at which all electromagnetic waves travel in a vacuum

c = 3.00 E8 m/s

Question 4

equation for the speed of light

Answer 4

c = frequency * wavelength

Question 5

wavelengths of the visible spectrum

Answer 5

400nm (violet) - 700nm (red)

Question 6

rectilinear propagation

Answer 6

when light travels in a straight line through a homogenous medium

Question 7

reflection

Answer 7

rebounding of incident light waves at the boundary of a medium

bounce of second medium, travel back through first medium

Question 8

law of reflection

Answer 8

theta 1 = theta 2

where theta 1 is the incident angle, theta 2 is the reflected angle and the normal is drawn perpendicular to the boundary medium

Question 9

real image

Answer 9

light converges at the position of the image created by a mirror

Has POSITIVE image distance, in front of the mirror

can be projected onto a screen

Question 10

virtual image

Answer 10

light appears to, but DOES NOT actually, converge at the position of the image created by mirror

Has NEGATIVE image distance, behind the mirror

CANNOT be projected onto a screen

Question 11

plane mirror surface image

Answer 11

flat and reflective surface

always create VIRTUAL images because light remains in parallel and does not converge or diverge

image always appears equal distance behind the mirror as object is in front of it

Question 12

spherical mirrors

Answer 12

concave or convex with

Question 13

center of curvature

Answer 13

where the center of a spherical mirror would be if it were a complete sphere

Question 14

radius of curvature

Answer 14

what the radius of a spherical mirror would be if it were a complete sphere

Question 15

converging mirrors

Answer 15

concave mirrors

cause parallel incident rays to converge after reflection, causing a larger and closer image

Question 16

diverging mirrors

Answer 16

convex mirrors

cause parallel incident rays to diverge after reflection, causing smaller and further images

Question 17

focal length (f)

Answer 17

distance between mirror and focal point (F)

Question 18

focal length for all spherical mirrors

Answer 18

f = r/2

Question 19

object distance (o)

Answer 19

distance between object and mirror

Question 20

image distance (i)

Answer 20

distance between image and mirror

Positive = real image, in front of the mirror
Negative = virtual image, behind the mirror

Question 21

equation relating focal length, object distance, and image distance

Answer 21

1/f = 1/o + 1/i

= 2/r for spherical
= 0 for plane

Question 22

focal length for all plane mirrors

Answer 22

f = infinity

Question 23

equation for magnification (m)

Answer 23

m = - i / o

negative = inverted image
positive = upright image

Question 24

where does a ray parallel to the axis reflect

Answer 24

thought the focal point

Question 25

where does a ray through the focal point reflect

Answer 25

parallel to the axis

Question 26

where does a ray at the center of the mirror reflect

Answer 26

at same angle relative to normal

Question 27

refraction

Answer 27

bending of light as it passes from one medium into another and changes its speed

Question 28

equation for index of refraction

Answer 28

n = c/v refraction index = speed of light / speed in particular medium

Question 29

snell's law for light that passes from one medium to another

Answer 29

n1 sin theta 1 = n2 sin theta 2

Question 30

where does light bend as it enters a medium with a higher refractive index

Answer 30

n2 > n1...therefore...sin theta 1 > sin theta 2...bends towards normal

Question 31

where does light bend as it enters a medium with a lower refractive index

Answer 31

n1 > n2...therefore...sin theta 2 > sin theta 1...bends away from the normal

Question 32

critical angle

Answer 32

refracted angle theta 2 = 90 degrees refracted angle passes along interface between the two media

Question 33

total internal reflection

Answer 33

occurs when angle of incidence is greater than the critical angle, and refracted light is reflected back into the original medium

Question 34

converging lenses

Answer 34

- thicker at center

Question 35

diverging lenses

Answer 35

- thin at center

Question 36

where does a ray parallel to the axis refract

Answer 36

through the focal point to the front face of the lens

Question 37

where does a ray through or toward the focal point before reaching the lens refract

Answer 37

refracts parallel to the axis

Question 38

where does a ray to the center of the lens refract

Answer 38

continues straight with no refraction

Question 39

lensmaker's equation | thickness is not negligible

Answer 39

1/f = (n - 1)( 1/r1 - 1/r2 ) where r1 is the radius of the first lens surface and r2 is the radius of the second lens surface

Question 40

which kinds of mirrors and lenses are similar and have similar properties

Answer 40

concave mirrors and convex lenses = converging convex mirrors and concave lenses = diverging

Question 41

equation for power of a lens

Answer 41

P = 1/f unit of power is diopters

Question 42

equation for equivalent focal length

Answer 42

1/f = 1/f1 + 1/f2 + 1/f3...

Question 43

equation for equivalent power

Answer 43

1/P = 1/P1 + 1/P2 + 1/P3...

Question 44

spherical aberration

Answer 44

blurring of the periphery of an image as a result of inadequate reflection of parallel beams at the edge of a mirror or inadequate refraction of parallel beams at the edge of a lens

Question 45

dispersion

Answer 45

when various wavelengths of light separate from each other

Question 46

chromatic aberration

Answer 46

dispersive effect within a spherical lens white light is split, causing rainbow images

Question 47

diffraction

Answer 47

the splitting out of light as it passes through a narrow opening or around an obstacle

Question 48

fringe pattern of single slit diffraction with lens

Answer 48

central bright fringe (zeroth) twice as wide as fringes on either side location of dark fringes is a * sin theta = n * wavelength

Question 49

what do bright fringes (maxima) represent

Answer 49

where light waves experience constructive interference

Question 50

what do dark fringes (minima) represent

Answer 50

where light waves experience destructive interference

Question 51

fringe patter of double slit diffraction with lens

Answer 51

central bright fringe (zeroth) equal wide as fringes on either side location of dark fringes is d sin theta = (n + 0.5) * wavelength

Question 52

diffraction gratings

Answer 52

multiple slits arranged in patterns that creates prism-like patterns as different wavelengths interact thin film interference, CDs...

Question 53

plane-polarized light

Answer 53

light with all electric field vectors parallel

Question 54

circular polarized light

Answer 54

light with uniform amplitude and continuously changing direction, causing helical orientation in the propagating waves