In the equation φ = (2πa/λ) sin θ for single-slit diffraction, φ is: 

A. the angle to the first minimum 

B. the angle to the second maximum 

C. the phase angle between the extreme rays 

D. Nπ where N is an integer 

E. (N + 1/2)π where N is an integer

The widths of the lines produced by monochromatic light falling on a diffraction grating can be reduced by: 

A. increasing the wavelength of the light 

B. increasing the number of rulings without changing their spacing 

C. decreasing the spacing between adjacent rulings without changing the number of rulings

D. decreasing both the wavelength and the spacing between rulings by the same factor 

E. increasing the number of rulings and decreasing their spacing so the length of the grating remains the same

A mixture of 450-nm and 900-nm light is incident on a diffraction grating. Which of the following is true? 

A. all lines of the 900-nm light coincide with even order lines of the 450-nm light 

B. all lines of the 450-nm light coincide with even order lines of the 900-nm light 

C. all lines of the 900-nm light coincide with odd order lines of the 450-nm light 

D. None of the lines of the 450-nm light coincide with lines of the 900-nm light 

E. All of the lines of the 450-nm light coincide with lines of the 900-nm light

An air wedge is formed from two glass plates that are in contact at their left edges. There are ten dark bands when viewed by reflection using monochromatic light. The left edge of the top plate is now slowly lifted until the plates are parallel. During this process: 

A. the dark bands crowd toward the right edge 

B. the dark bands remain stationary 

C. the dark bands crowd toward the left edge 

D. the dark bands spread out, disappearing off the right edge 

E. the dark bands spread out, disappearing off the left edge

Waves from two slits are in phase at the slits and travel to a distant screen to produce the second minimum of the interference pattern. The difference in the distance traveled by the waves is: 

A. half a wavelength 

B. a wavelength 

C. three halves of a wavelength 

D. two wavelengths 

E. five halves of a wavelength

A point source of monochromatic light is placed in front of a soccer ball and a screen is placed behind the ball. The light intensity pattern on the screen is best described as: 

A. a dark disk on a bright background 

B. a dark disk with bright rings outside 

C. a dark disk with a bright spot at its center 

D. a dark disk with a bright spot at its center and bright rings outside 

E. a bright disk with bright rings outside

Huygens’ construction can be used only: 

A. for light 

B. for an electromagnetic wave

C. if one of the media is vacuum (or air) 

D. for transverse waves 

E. for all of the above and other situations

Monochromatic light is normally incident on a diffraction grating. The m^th order line is at a diffraction angle θ and has width w. A wide single slit is now placed in front of the grating and its width is then slowly reduced. As a result: 

A. both θ and w increase 

B. both θ and w decrease 

C. θ remains the same and w increases 

D. θ remains the same and w decreases 

E. θ decreases and w increases

The dispersion of a diffraction grating indicates: 

A. the resolution of the grating 

B. the separation of lines of the same order 

C. the number of rulings in the grating 

D. the width of the lines 

E. the separation of lines of different order for the same wavelength

Waves from two slits are in phase at the slits and travel to a distant screen to produce the third side maximum of the interference pattern. The difference in the distance traveled by the waves is: 

A. half a wavelength 

B. a wavelength 

C. three halves of a wavelength 

D. two wavelengths 

E. three wavelengths