Explore the connections.

• 4.4.1(a) Define and describe progressive, longitudinal and transverse waves.
• 4.4.1(b)(i) Define displacement, amplitude, wavelength, period, phase difference, frequency and speed of a wave.
• 4.4.1(b)(ii) Use an oscilloscope to determine frequency and wave characteristics.
• 4.4.1(c) Use 1/T = f to relate period and frequency.
• 4.4.1(d) Use the wave equation v = fλ.
• 4.4.1(e) Interpret graphs of transverse and longitudinal waves.
• 4.4.1(f)(i) Describe reflection, refraction, polarisation and diffraction of waves.
• 4.4.1(f)(ii) Demonstrate wave effects using a ripple tank.
• 4.4.1(f)(iii) Observe polarisation effects using microwaves and light.
• 4.4.1(g) Define intensity I = P / A and recognise that intensity ∝ amplitude².
• 4.4.2(a) Describe the electromagnetic spectrum and properties of electromagnetic waves.
• 4.4.2(b) Recall orders of magnitude of wavelengths from radio waves to gamma rays.
• 4.4.2(c) Describe plane-polarised waves and polarisation of electromagnetic waves.
• 4.4.2(d)(i) Define refraction of light, refractive index n = c / v, and Snell’s law n₁sinθ₁ = n₂sinθ₂.
• 4.4.2(d)(ii) Use ray boxes and transparent blocks to investigate refraction and total internal reflection.
• 4.4.2(e) Define critical angle using sin c = 1 / n and describe total internal reflection.
• 4.4.3(a)(i) State the principle of superposition of waves.
• 4.4.3(a)(ii) Demonstrate superposition using sound, light and microwaves.
• 4.4.3(b) Use graphical methods to illustrate superposition of waves.
• 4.4.3(c) Define and describe interference, coherence, path difference and phase difference.
• 4.4.3(d) Explain constructive and destructive interference in terms of path and phase difference.
• 4.4.3(e) Describe two-source interference with sound and microwaves.
• 4.4.3(f) Describe Young’s double-slit experiment using visible light and explain its significance in demonstrating wave behaviour.
• 4.4.3(g)(i) Use interference equation λ = ax / D for all waves where a ≪ D.
• 4.4.3(g)(ii) Determine the wavelength of light using a double slit at AS. Diffraction gratings and the grating equation are assessed only at A level.
• 4.4.4(a) Describe stationary (standing) waves using microwaves, stretched strings and air columns.
• 4.4.4(b) Interpret graphical representations of stationary waves.
• 4.4.4(c) Compare stationary and progressive waves.
• 4.4.4(d) Define nodes and antinodes.
• 4.4.4(e)(i) Describe stationary wave patterns for stretched strings and air columns in closed and open tubes.
• 4.4.4(e)(ii) Determine speed of sound in air by forming stationary waves in a resonance tube.
• 4.4.4(f) Understand that the separation between adjacent nodes or antinodes is equal to λ / 2.
• 4.4.4(g) Define the fundamental mode (first harmonic) and describe higher harmonics.

H156 v2.0 · May 2026