Consider a single-slit diffraction pattern caused by a slit of width a. There is a maximum if sin θ is equal to: 

A. slightly more than 3λ/2a 

B. slightly less than 3λ/2a 

C. exactly 3λ/2a 

D. exactly λ/2a 

E. very nearly λ/2a

Which of the following is true for Bragg diffraction but not for diffraction from a grating? 

A. Two different wavelengths may be used 

B. For a given wavelength, a maximum may exist in several directions 

C. Long waves are deviated more than short ones 

D. There is only one grating spacing 

E. Maximum occur only for particular angles of incidence

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 person with her eye relaxed looks through a diffraction grating at a distant monochromatic point source of light. The slits of the grating are vertical. She sees: 

A. one point of light 

B. a hazy horizontal strip of light of the same color as the source 

C. a hazy strip of light varying from violet to red 

D. a sequence of horizontal points of light 

E. a sequence of closely spaced vertical lines

Light of wavelength is normally incident on some plane optical device. The intensity pattern shown is observed on a distant screen (θ is the angle measured from the normal of the device). The device could be:

A. a single slit of width W 

B. a single slit of width 2W 

C. two narrow slits with separation W 

D. two narrow slits with separation 2W 

E. a diffraction grating with slit separation W

In the equation d sin θ = mλ for the lines of a diffraction grating d is: 

A. the number of slits 

B. the slit width 

C. the slit separation 

D. the order of the line 

E. the index of refraction

The resolving power of a telescope can be increased by: 

A. increasing the objective focal length and decreasing the eyepiece focal length 

B. increasing the lens diameters 

C. decreasing the lens diameters 

D. inserting a correction lens between objective and eyepiece 

E. none of the above

At a diffraction line phasors associated with waves from the slits of a multiple-slit barrier: 

A. are aligned 

B. form a closed polygon 

C. form a polygon with several sides missing 

D. are parallel but adjacent phasors point in opposite directions 

E. form the arc of a circle

Two nearly equal wavelengths of light are incident on an N-slit grating. The two wavelengths are not resolvable. When N is increased they become resolvable. This is because: 

A. more light gets through the grating 

B. the lines get more intense 

C. the entire pattern spreads out 

D. there are more orders present 

E. the lines become more narrow 

As more slits with the same spacing are added to a diffraction grating the lines: 

A. spread farther apart 

B. move closer together 

C. become wider 

D. becomes narrower 

E. do not change in position or width