IB Physics SL C.3.11 Resolution and Rayleigh Criterion

Practise applying diffraction-limited angular resolution and the Rayleigh criterion to decide whether two sources are resolved and how wavelength or aperture changes image detail.

Exam points

calculate the diffraction angle or Rayleigh limit with θ ≈ 1.22λ/D for a circular aperture
compare source angular separation with the criterion to decide whether the images are just resolved
predict improved resolution for shorter wavelength or larger aperture without reversing the trend

[Maximum number: 2]

This question is about diffraction and resolution.

Monochromatic light is incident normally on a single narrow slit and gives rise to a diffraction pattern on a screen.

Figure for Question C.3.11—Resolution and Rayleigh criterion question 1 — IB Physics SL

Two lamps emit light of wavelength 620 nm . The lights are observed through a circular aperture of diameter 1.5 mm from a distance of 850 m . Calculate the minimum distance between the lamps so that they are resolved.

equating $1.22 \frac{\lambda}{b}$ to $\frac{x}{D}$ ; 0.43 (m);

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C.3.11—Resolution and Rayleigh criterion question 1