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A student has a diffraction grating that is marked 3.5 × 103 lines per m.
1
(a) Calculate the percentage uncertainty in the number of lines per metre suggested by this
marking.
percentage uncertainty = ..................................... %
(1)
(b) Determine the grating spacing.
grating spacing = ..................................... mm
(2)
(c) State the absolute uncertainty in the value of the spacing.
absolute uncertainty = ..................................... mm
(1)
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(d) The student sets up the apparatus shown in Figure 1 in an experiment to confirm the value
marked on the diffraction grating.
Figure 1
The laser has a wavelength of 628 nm. Figure 2 shows part of the interference pattern that
appears on the screen. A ruler gives the scale.
Figure 2
Use Figure 2 to determine the spacing between two adjacent maxima in the
interference pattern. Show all your working clearly.
spacing = ..................................... mm
(1)
(e) Calculate the number of lines per metre on the grating.
number of lines = .....................................
(2)
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A student has a diffraction grating that is marked 3.5 × 103 lines per m.
1
(a) Calculate the percentage uncertainty in the number of lines per metre suggested by this
marking.
percentage uncertainty = ..................................... %
(1)
(b) Determine the grating spacing.
grating spacing = ..................................... mm
(2)
(c) State the absolute uncertainty in the value of the spacing.
absolute uncertainty = ..................................... mm
(1)
@TOPhysicsTutor facebook.com/TheOnlinePhysicsTuto
Page 2 of 23
, theonlinephysicstutor.com
(d) The student sets up the apparatus shown in Figure 1 in an experiment to confirm the value
marked on the diffraction grating.
Figure 1
The laser has a wavelength of 628 nm. Figure 2 shows part of the interference pattern that
appears on the screen. A ruler gives the scale.
Figure 2
Use Figure 2 to determine the spacing between two adjacent maxima in the
interference pattern. Show all your working clearly.
spacing = ..................................... mm
(1)
(e) Calculate the number of lines per metre on the grating.
number of lines = .....................................
(2)
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Page 3 of 23
