IB Physics HL C.3.7 Path Difference Question Bank

Practise IB Physics HL C.3.7 by solving path-difference, phase and interference conditions across optical, sound and crystal-wave problems.

[Maximum number: 3]

A beam of coherent monochromatic light from a distant galaxy is used in an optics experiment on Earth.

The beam is incident normally on a double slit. The distance between the slits is 0.300 mm . A screen is at a distance D from the slits. The diffraction angle $\theta$ is labelled.

Figure for Question C.3.7—Path difference question 1 — IB Physics HL

A series of dark and bright fringes appears on the screen. Explain how a dark fringe is formed.

superposition of light from each slit / interference of light from both slits with path/phase difference of any half-odd multiple of wavelength/any odd multiple of $\pi$ (in words or symbols) producing destructive interference

Marking guidance:

Ignore any reference to crests and troughs.

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C.3.7—Path difference question 1