WorksheetsAP Physics 2 Light Waves Review
Total questions: 19
Worksheet time: 10mins
A diffraction grating is used to measure the wavelength of monochromatic light, as shown in the diagram.
The spacing of the slits in the grating is 1.00 x10-6 m. The angle between the first order diffraction maxima is 70.0o.
What is the wavelength of the light?
287 nm
470 nm
574 nm
940 nm
Interference of light is evidence that:
the speed of light is very large
light is a transverse wave
light is electromagnetic in character
light is a wave phenomenon
In a Young's double-slit experiment the centre of a bright fringe occurs wherever waves from the slits differ in the distance they travel by a multiple of:
quarter of a wavelength.
half a wavelength.
a wavelength.
three-fourths of a wavelength.
In a Young's double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance D must be changed to:
D/2
D 2
2D
4D
For destructive interference, the path difference is:
odd number of half wavelengths
even number of half wavelengths
whole number of wavelengths
even whole number of wavelengths
Constructive interference happens when two waves are:
out of phase.
zero amplitude.
in phase.
Two waves with phase difference 180° have resultant of amplitude
one.
zero.
same as the single wave.
doubles the single wave.
Extra distance travelled by one of waves compared with other is called
path.
displacement.
phase difference.
path difference.
What principle is responsible for light spreading as it passes through a narrow slit?
refraction
polarization
diffraction
interference
What principle is responsible for alternating light and dark bands when light passes through two or more narrow slits?
refraction
polarization
diffraction
interference
Light of wavelength 575 nm falls on a double-slit and the third order bright fringe is seen at an angle of 6.5o. What is the separation between the double slits?
5.0 micro-m
10 micro-m
15 micro-m
20 micro-m
The width of central maximum is directly proportional to the wavelength of light.
True
False
Figure 2 shows three experiments for studying the interaction of monochromatic light with thin films of glass of various thickness t. The eye represents the position of the observer. The observer sees constructive interference in
I only
II only
III only
I and III only
II and III only
A thin coating, of refractive index 1.2, is applied to a glass camera lens, of refractive index n > 1.2, to minimize the intensity of the light reflected. The wavelength of the light is . The coating thickness required to minimize the intensity of reflected light is
2λ
2×1.2λ
41.2λ
4×1.2λ
The thickness of a human hair is to be measured using the interference pattern produced by an air wedge. Red light with a wavelength of 638 nm is used on an air wedge that is 25.0 cm long. If 10 bright fringes are counted across 1.06 cm in the air wedge, what is the thickness of the hair?
752 µm
576 µm
75.2 µm
57.6 µm
780 µm
A construction company designs a new office tower with an outer surface mostly made of glass (nglass = 1.52). The company wishes that the glass appear a reddish-orange without having to use coloured glass. Instead, a thin film (nfilm = 1.65) is used that maximizes the reflection of that colour of light (wavelength 615 nm). What thickness would this film need to be?
1.5 x 10-8 m
2.67 x 10-8 m
8.67 x 10-8 m
1.2 mm
9.32 x 10-8 m
The interference pattern created by monochromatic light in an air wedge is used to measure the thickness of an object. Which of the following changes would cause the spacing between adjacent fringes to increase?
Use a light source with a higher frequency.
Increase the thickness of the object being measured.
Use a light source with a longer wavelength.
Use a shorter air wedge.
The index of refraction of the thin film (water) is higher than air as shown in Figure above - the reflected ray will undergo a phase change of ½λ ( or π rad).
True
False
What is the path difference of the reflected rays traveling through the film?
t
2nt
t/2
0
