Physics P
Review
11
1.
Unit 11 Review: Light and Optics
Light and Optics
Describe the image formed by a plane mirror.
Include the kind of image, the orientation of the
image, the size of the image, and the location of the
image.
11.
What is the critical angle for light traveling from
quartz into crown glass?
12.
Yellow light of a certain wavelength is incident
upon two slits separated by 22.5 µm. A screen is
placed 1.2 m away from the slits. The distance to
the first–order bright line is 31.4 mm. What is the
wavelength of the light?
2.
Visible light has a frequency that ranges from
about 4.0 × 1014 Hz to about 7.5 × 1014 Hz. What is
the range of wavelengths for visible light?
3.
A light ray strikes a plane mirror at an angle of 41˚
to the normal. How many degrees must the mirror
be rotated so that the angles of incidence and
reflection are both zero and the reflected light
follows the same path as the incident light?
13.
A certain laser emits light with a wavelength of
696 nm. The laser is directed at a double slit and a
screen is placed 0.9 m from the slits. The first–
order bright line appears 36.5 mm from the central
bright line. What is the distance between the slits?
4.
A beam of light traveling through air strikes flint
glass at an angle of 31˚ to the normal. At what
angle does the beam enter the flint glass?
14.
5.
A beam of light traveling through water is incident
upon an unknown type of glass at an angle of 45˚
to the normal and is refracted at an angle of 33.6˚
to the normal.
a.
What is the index of refraction for the
unknown type of glass?
b.
What is the speed of light in the unknown
type of glass?
Green light with a wavelength of 545 nm is
incident upon two slits separated by 18 µm. A
screen is set up to view the interference pattern
produced and the first–order bright line is 26.4 mm
from the central bright line. How far is the screen
from the double slit?
15.
A single–slit diffraction experiment is set up using
light from a He–Cd laser (λ = 442 nm). A screen is
placed 0.98 m from the slit and the central bright
line produced by the experiment has a width of
21.3 cm. What is the width of the slit?
16.
A single–slit diffraction experiment is set up using
a slit with a width of 10 µm. The screen is placed
0.9 m from the slit and the distance from the
central bright band to the first dark line is 0.55 cm.
What is the wavelength of the light used?
17.
The aperture through which light enters the human
eye is called the iris. The average human iris has a
diameter of 5 mm. What is the physical limit of the
height of an object viewed from 6 m away?
18.
Coherent light of wavelength 642 nm is incident
upon a pair of slits separated by 21 µm. If a screen
is placed 0.55 m from the slits, how far from the
central bright band is the second–order bright
band?
19.
Light of an unknown wavelength falls on two slits
separated by 1.9 × 10–5 m. A first–order bright
band appears 12.4 mm from the central bright band
on a screen that is placed 0.45 m from the slits.
Find the wavelength of the light.
6.
7.
8.
A beam of yellow light has a wavelength of
2.43 × 10–7 m in an unknown medium. The vacuum
wavelength is 589 nm.
a.
What is the index of refraction of the
unknown medium?
b.
Based on Table 18–1 on page 486 of your
textbook, what do you think the unknown
substance is?
An even layer of oil floats on top of water
(noil = 1.15). A beam of light strikes the oil at an
angle of 32.1˚ to the normal. What is the beam’s
angle of refraction in the water?
A beam of light has a wavelength of 550 nm.
While traveling through an unknown substance, the
light has a wavelength of 5 × 10–7 m. What is the
index of refraction of the unknown substance?
9.
A beam of light traveling through water strikes the
boundary between the water and air at an angle of
25˚ to the normal. At what angle does the light
enter the air?
10.
Light travels at a speed of 1.85 × 108 m/s through
an unknown medium.
a.
What is the index of refraction of the
medium?
b.
Based on Table 18–1 on page 486 of your
textbook, what do you think the medium is?
1
Physics P
Unit 11 Review: Light and Optics
1
The image formed by a plane mirror is a
virtual image that is upright, the same
size as the object and located at the
same distance behind the mirror as the
object is located in front of the mirror.
2
c = fλ
c
λ=
f
5b
6a
3.00 × 108 m/s
4.0 × 1014 Hz
λ = 7.5 × 10 −7 m
n=
λ = 750 nm
c
v
f λ0
f λ1
λ0
λ1
5.89' × '10−7 'm
2.43' × '10−7 'm
n = 2.42
c = fλ
n=
c
f
3.00 × 108 m/s
7.5 × 1014 Hz
λ = 4.0 × 10 −7 m
λ=
6b
Diamond
7
n1 sin θ1 = n2 sin θ 2
n
sin θ1 = 2 sin θ 2
n1
λ = 400 nm
3
41˚
4
n1 sinθ1 = n2 sinθ2
1.15
sin (32.1˚)
1.33
sin θ1 = 0.459
sin θ1 =
sinθ1 =
n2
n1
θ1 = sin −1 ( 0.459 )
sinθ2
θ1 = 27˚
1.00
sinθ1 =
sin 31˚
1.62
sinθ1 = 0.318
( )
(
θ1 = sin−1 0.318
8
)
θ1 = 19˚
5a
n=
n=
λ=
λ=
c
v
c
v=
n
3.00 × 108 m/s
v=
1.70
v = 1.77 × 108 m/s
n=
n1 sin θ1 = n2 sin θ 2
sin θ 2
n1 = n2
sin θ1
n1 = (1.33)
sin ( 45˚)
sin (33.6˚)
n1 = 1.70
2
c
v
fλ
n= 0
f λ1
λ
n= 0
λ1
550 nm
n=
5 × 10 −7 m
n = 1.1
n=
Physics P
9
Unit 11 Review: Light and Optics
n1 sin θ1 = n2 sin θ 2
14
n2
sin θ 2
n1
1.33
sin θ1 =
sin ( 25˚)
1.00
sin θ1 = 0.562
sin θ1 =
(
θ1 = sin −1 ( 0.562 )
θ1 = 34˚
10a
15
c
v
3.00 × 108 m/s
n=
1.85 × 108 m/s
n = 1.62
n=
2λ L
w
λL
w=
x1
2x1 =
( 442 nm )( 0.98)
w = 2.0 µ m
n1 sin θ1 = n2 sin θ 2
16
λ
θ c = sin −1 ( 0.987)
λ
λ
θ c = 81˚
2λ L
w
wx1
=
L
(10 µm )( 0.55 cm )
=
0.9 m
= 6.1 × 10 −8 m
= 61 nm
2x1 =
λ
1.52
sin ( 90˚)
1.54
sin θ c = 0.987
sin θ c =
61 nm is not visible but rather UV
xd
λ=
L
(31.4 mm )( 22.5 µm )
λ=
1.2 m
λ = 5.89 × 10 −7 m
17
xobj
xd
L
λL
d=
x
( 696 nm )( 0.9 m )
d=
36.5 mm
d = 1.72 × 10 −5 m
d = 17.2 µ m
λ=
1.22 λ Lobj
D
1.22 λ Lobj
=
D
(1.22)( 550 nm )( 6 m )
=
5 mm
−4
= 8 × 10 m
xobj =
xobj
λ = 589 nm
13
)
21.3 cm
w = 2.0 × 10 −6 m
n
sin θ1 = 2 sin (θ 2 )
n1
12
)(
w=
10b Flint glass
11
xd
L
xd
L=
λ
26.4%mm 18%µm
L=
545%nm
L = 0.87%m
λ=
xobj
xobj = 0.8 mm
xobj = 800 µ m
3
Physics P
18
19
Unit 11 Review: Light and Optics
xd
L
λL
x=
d
( 642 nm )( 0.55 m )
x=
21 µ m
x = 0.017 m
x = 17 mm
λ=
λ=
λ=
xd
L
(12.4 mm ) 1.9 × 10 −5 m
(
)
0.45 m
λ = 5.2 × 10 m
λ = 520 nm
−7
4