Target: 10 Questions in 10 minutes

An IB Physics data booklet is helpful

1. A student attempts to sketch the intensity graph for an interference pattern produced when a laser is directed at a single slit.

Which of these graphs best shows this intensity pattern?

single slit interference patterns x4

2. The formula for single slit interference is θ = λ/b.

λ is the wavelength of the wave directed at the single slit. What do θ and b represent?

 θ b
A
 angle from centre to next maximum width of the slit
B
 angle from centre to first minimum width of the slit
C
 angle from centre to next maximum width of central maximum
D
 angle from centre to first minimum width of central maximum

3. Which of the two statements are true for single slit interference?

I. Single slit interference only occurs with transverse waves
II. Blue light produces a larger value of θ than red light

  
  • A. Both are true
  • B. I only
  • C. II only
  • D. Neither are true

4. A single slit pattern is produced by a laser. The angle subtended by the central maximum is dependent on several factors.

Which of the following changes will make the maximum wider?

  • A. Increase the width of the slit.
  • B. Increase the height of the slit.
  • C. Increase the wavelength of the laser light.
  • D. Increase the intensity of the laser light.
5. Green monochromatic light is directed at a single slit, a double slit and a diffraction grating. The patterns produced are shown here:

X:
Y:
Z:
 

Which of the following correctly identifies the patterns X and Y?

 X Y
A
 diffraction grating single slit
B
 single slit double slit
C
 double slit diffraction grating
D
 double slit single slit


Q6&7. The diagram below shows a 'Young's double slit' light intensity distribution.

double slit interference pattern - red

 kdKeller
wikimedia commons

6. What causes the overall envelope shown by the black line?

  • A. Interference between 2 slits.
  • B. Constructive interference between the laser and reflected light.
  • C. Single slit interference.
  • D. Interference from 3 or more slits.

7. What would happen to the envelope shown by the black line if the individual slits were made wider, but the spacing between the slits remains the same?

  • A. The black line peaks will be higher and more widely spaced.
  • B. The black line peaks will be higher and closer together.
  • C. The black line peaks will be the same height, but more widely spaced.
  • D. The black line peaks will be the same height, but closer together

 

8. A diffraction grating has 100 lines per millimetre. This means the spacing between the lines is:

  • A. 10-1 m
  • B. 10-3 m
  • C. 10-5 m
  • D. 10-7 m

9. A different grating has a line spacing of 2 x10-6 m. If the wavelength of light used is 400 nm, the first order fringe (where n=1) will occur when:

  • A. sin θ = 0.2
  • B. sin θ = 0.02
  • C. sin θ = 0.5
  • D. sin θ = 0.05

10. When viewing a pattern produced by a diffraction grating, what is the maximum possible value for θ in the diffraction grating formula?

  • A. < 450
  • B. < 900
  • C. < 1800
  • D. < 3600