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EnglandPhysics

3.3 Waves

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do waves spread out through gaps and around obstacles, and how does a diffraction grating split light into spectra?

Diffraction of waves at a single slit, the appearance of the single-slit pattern with white light and monochromatic light, the diffraction grating, the grating equation, and its applications in spectra.
A focused answer to AQA A-Level Physics 3.3.2.3, covering diffraction at a single slit, the single-slit pattern with monochromatic and white light, the diffraction grating, the grating equation and applications in producing spectra.
10 min answer →

How do coherent waves interfere to produce bright and dark fringes, and what is needed to see a stable pattern?

The principle of superposition, path difference and phase difference, constructive and destructive interference, the conditions of coherence, Young's double-slit experiment, and the double-slit fringe equation.
A focused answer to AQA A-Level Physics 3.3.2.1 and 3.3.2.2, covering superposition, path and phase difference, constructive and destructive interference, coherence, Young's double-slit experiment and the fringe-spacing equation.
10 min answer →

What is a progressive wave, and how are its frequency, wavelength, speed and phase related?

Progressive waves and the transfer of energy, amplitude, frequency, wavelength, period, speed and phase, the wave equation, and the difference between transverse and longitudinal waves including polarisation.
A focused answer to AQA A-Level Physics 3.3.1.1 and 3.3.1.2, covering progressive waves and energy transfer, the wave quantities, the wave equation, transverse and longitudinal waves, and polarisation.
10 min answer →

Why do waves change direction when they cross a boundary, and when does light undergo total internal reflection?

Refraction and the refractive index of a substance, Snell's law at a boundary, the critical angle, total internal reflection, and the operation of optical fibres.
A focused answer to AQA A-Level Physics 3.3.2.4, covering refraction and refractive index, Snell's law, the critical angle, total internal reflection, and how optical fibres guide light.
10 min answer →

How do two progressive waves combine to form a standing wave, and why does it have fixed nodes and antinodes?

The formation of stationary waves from two progressive waves travelling in opposite directions, nodes and antinodes, the differences between stationary and progressive waves, and resonance on strings and in air columns.
A focused answer to AQA A-Level Physics 3.3.1.3, covering how stationary waves form from two progressive waves, nodes and antinodes, the differences between stationary and progressive waves, and the harmonics of a string fixed at both ends.
10 min answer →