Name: 
 

Physics 12 - Unit 4 Quiz


True/False
Indicate whether the sentence or statement is true or false.
 

1. 
Two ripple tank sources vibrating in phase produce an interference pattern. If the frequency of the two sources increases, the number of nodal lines increases.
 

2. 
The wave theory predicts that light slows down when it travels from air to glass, whereas the Newtonian particle theory predicts it will speed up.
 

3. 
All wave properties of light can be explained with the wave model.
 

4. 
Two rays of light from the same source interfere destructively if their path lengths differ by 3.5l
 

5. 
If a Young’s double-slit apparatus, having operated in air, were to be submerged in water, the fringe pattern would become less spread out.
 

6. 
If a Young’s double-slit apparatus, having operated with a monochromatic red source, were to be operated with a monochromatic blue source, the fringe pattern would become more spread out.
 

7. 
When using a single slit, the distance between adjacent dark fringes will increase if the slit width is decreased, all other factors being kept constant.
 

8. 
All waves have the same properties as electromagnetic waves.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

9. 
In a ripple tank, the wavelength l1 of waves in the deep water is 2.0 cm. The wavelength l2 of waves in the shallow water is 1.2 cm. The wave generator has a frequency of 12 Hz. The speed of the waves in the deep water is
a.
2.0 cm/s
b.
6.0 cm/s
c.
12 cm/s
d.
14 cm/s
e.
24 cm/s
 

10. 
A narrow beam of light is transmitted through different media as shown in Figure 1. If v1, v2, and v3 are the respective speeds of light in the three media, then

p12u4_files/i0120000.jpg      Figure 1
a.
v1 > v2 > v3
b.
v3 > v2 > v1
c.
v3 > v1 > v2
d.
v2 > v1 > v3
e.
v1 > v3 > v2
 

11. 
When a transverse wave travelling along a string reaches the junction with a lighter string, the wave is
a.
totally reflected at the junction
b.
partially transmitted, with a change of phase
c.
transmitted, forming a standing-wave pattern in the lighter string
d.
reflected so as to form a node at the junction
e.
partially reflected without a change in phase
 

12. 
A nodal line pattern is produced by two point sources vibrating in phase in a ripple tank. A point P on the second nodal line is 37.0 cm from the one source and 28.0 cm from the other. The wavelength is
a.
18.0 cm
b.
13.5 cm
c.
9.0 cm
d.
6.0 cm
e.
4.5 cm
 

13. 
Monochromatic light in Figure 2 passes through slit S in a cardboard sheet, then falls onto a metal sheet containing slits B and C, and finally produces an interference pattern, centred at P, onto a screen. All the slits are the same width.

p12u4_files/i0150000.jpg
Figure 2

The intensity pattern on the screen will not change if
a.
the separation between slits B and C is increased
b.
the width of slits B and C is decreased
c.
the distance from the metal sheet to the screen is decreased
d.
the distance between the cardboard and metal sheets is increased
e.
the wavelength is decreased
 

14. 
Of the five diagrams in Figure 3, choose the one which most accurately illustrates single-slit diffraction from a monochromatic source.

p12u4_files/i0160000.jpg      Figure 3
a.
a
b.
b
c.
c
d.
d
e.
e
 

15. 
Red light, of wavelength l in soapy water, is viewed through a thin soap film held vertically (Figure 4). At the second dark area from the top, the thickness of the film is

p12u4_files/i0170000.jpg            Figure 4
a.
l
b.
p12u4_files/i0170001.jpgl
c.
p12u4_files/i0170002.jpgl
d.
p12u4_files/i0170003.jpgl
e.
very much less than l
 

16. 
The condition necessary for maximum transmission of the light energy passing through the coating on the exterior of the lens in Figure 5 is that

p12u4_files/i0180000.jpg      Figure 5
a.
rays 1 and 2 interfere constructively
b.
the coating be more transparent than the lens
c.
rays 3 and 4 interfere destructively
d.
the speed of light in the coating be less than the speed in the lens
e.
the total light energy reflected be a minimum
 

Matching
 
 
Match the scientist to the discovery or innovation important to the history of the wave theory of light discussed in this unit.
a.
Gabor
g.
Maxwell
b.
Grimaldi
h.
Michelson
c.
Hertz
i.
Newton
d.
Huygens
j.
Poisson
e.
Land
k.
Young
f.
Marconi
 

17. 
diffraction of light at two successive slits
 

18. 
diffraction of light around a small disk
 

19. 
mathematical theory of electromagnetic waves
 

20. 
holography
 

21. 
interferometer
 

22. 
particle theory of light
 

23. 
commercially viable polarizing filters
 

24. 
transmission of radio signals
 

25. 
creation and detection of radio waves
 

26. 
two-slit interference
 

27. 
wavelet model for propagation of wave fronts
 

Short Answer
 
 
Complete each sentence or statement.
 

28. 
At a constant speed, the wavelength of a wave is directly proportional to its _______ .
 

29. 
The frequency of a wave is determined by its _______  and does not change when the medium changes.
 

30. 
For a given slit, the amount of diffraction depends on the ratio _______ /_______ .
 

31. 
Increasing the separation of the sources in twin-source ripple tank diffraction increases the number of _______ lines.
 

32. 
Early attempts showing light interference were unsuccessful because the two sources were _______ and the _______  of light is very small.
 

33. 
The wave theory of light, as corroborated by Young’s experiment, explained all the then-known properties of light except transmission through a(n) _______ .
 

34. 
Polarization showed that light is a(n) _______ wave.
 

35. 
For single-slit diffraction, the smaller the slit width, the _______ the distance between maxima and minima.
 

36. 
The position of minima, or dark fringes, in single-slit diffraction is given by the equation _______ .
 

37. 
The larger the aperture of an optical instrument, the _______  the resolution.
 

38. 
The higher the frequency, the _______  the energy of an electromagnetic wave.
 



 
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