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PHYSICS CONNECTION

Refraction changes speed and wavelength together

Light crossing a stationary boundary keeps its frequency. A change in speed therefore changes its wavelength, and the boundary geometry determines its direction.

v = fλ n = c/v

Follow the reasoning

  1. Keep the frequency fixed across the boundary.
  2. Use refractive index to find speed or wavelength in the medium.
  3. Apply Snell’s law to the angles measured from the normal.
OFFICIAL OCR QUESTIONS

Try it in a past paper 3

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Specification outcomes (4)
  • 4.4.1(c) Use 1/T = f to relate period and frequency.
  • 4.4.1(d) Use the wave equation v = fλ.
  • 4.4.2(d)(i) Define refraction of light, refractive index n = c / v, and Snell’s law n₁sinθ₁ = n₂sinθ₂.
  • 4.4.2(e) Define critical angle using sin c = 1 / n and describe total internal reflection.
Official OCR AS specification ↗