Chapter 28: Physical Optics: Interference and Diffraction
Practice Questions




1.  

Two narrow slits spaced 100 microns apart are exposed to light of 600 nm. At what angle does the first minimum (dark space) occur in the interference pattern?

.003 radians
.006 radians
.006 degrees
.003 degrees


2.  

If a screen is 1 meter away from the two slits in question 1 where will be the first dark space on the screen?

3 m
3 cm
3 mm
.3 mm


3.  

In question 1 at what angle would the first off center maximum occur?

.003 radians
.006 radians
.009 radians
.012 radians


4.  

In question 2 where would the first off center maximum (bright line) occur?

0 mm
3 mm
6 mm
9 mm


5.  

How far would the screen have to be moved away in question 2 for the first dark line to move to the position of the first off center bright line?

.5 m
1 m
1.5 m
2 m


6.  

In question 2 what slit spacing would move the first dark line to the current position of the first off center bright line?

200 microns
150 microns
50 microns
25 microns


7.  

Light composed of red (700 nm) blue (400 nm) components falls on two slits and forms a central magenta appearing line on a screen 2 meters away. The nearest bright line to the central line is

magenta.
red.
blue.


8.  

Light composed of red (700 nm) blue (400 nm) components falls on two slits and forms a central magenta appearing line on a screen 2 meters away. If the slits have a separation of 100 microns, how far from the central magenta line will the first off-center magenta line appear?

2 cm
4.2 cm
5.6 cm
It will never appear.


9.  

Light striking a thin film (n=1.3) on a glass (n=1.5) surface appears green (550 nm) when viewed head on. What is the minimum thickness of the film?

50 nm
212 nm
275 nm
550 nm


10.  

The point of a soap (n=1.35) bubble closest to you appears red (550 nm) What is the minimum thickness of the film?

51 nm
102 nm
204 nm
408 nm


11.  

What must be the index of refraction of a 100 nm thick coating on glass if it is designed to eliminate reflection at 500 nm?

1
1.1
1.15
1.25
1.38


12.  

What is the angle of the first minimum in the diffraction pattern produced by 550 nm light incident upon a 550 nm slit?

0o
30o
45o
90o


13.  

What is the angle of the first minimum in the diffraction pattern produced by 550 nm light incident upon a 1100 nm slit?

0o
20o
30o
60o


14.  

What is the angle of the first minimum in the diffraction pattern produced by 550 nm light incident upon a 11000 nm slit?

0o
2.9o
20.1o
No minimum exists


15.  

In the previous question what would be the width of the central maximum on a screen 5 meters away?

11000 nm
25 cm
50 cm
2.5 m


16.  

In question 14 what would be the angle of the 10th minimum?

6o
15o
30o
Does not occur.


17.  

If a 200 inch ( 5 meter ) telescope where located in orbit what would be its resolution at a wavelength of 500 nm ?

1.22x10-7
2.44x10-7
1.22x10-6
2.44x10-6


18.  

The telescope in question 17 could resolve two point sources of light at the moon's distance of 3.8x108 meters separated by a distance of...

0.5 m
5 m
50 m
500 m


19.  

A diffraction grating has 8000 lines/cm and is exposed to light of 500 nm. The first order maxima occurs at

13.6o
23.6o
42o
52o


20.  

A diffraction grating has 8000 lines/cm and is exposed to light of 500 nm. Where is the second order maxima?

23.6o
53.1o
78.6o
Does not occur.


21.  

A diffraction grating has 8000 lines/cm and is exposed to light of 500 nm.If the light in question 19 had a wavelength of 700 nm the first maximum would be at

23o.
34o.
66o.
89o.


22.  

In the previous question where would the second order maximum be located?

38.4o
58.4o
88.4o
Does not occur.


23.  

Green (525 nm) and red (700) nm light strike a diffraction grating with 4000 lines/cm. In what order (m=?) would the red light have the same angle as the green light of the next higher order?

m=2
m=3
m=4
Does not occur.


24.  

What is the angle in the previous question at which the two colors are at the same angle?

57o
66o
86o
Does not occur.


25.  

If a diffraction grating has 5555 lines/cm, what maximum order m spectrum will occur for 600 nm light?

1
2
3
4


Practice Questions: Practice Questions by Carl Adler, East Carolina University. ©2002 by Prentice Hall, Inc.


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