Unit 2: Waves and Electricity
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2.3 - Waves and Particle Nature of Light
2.3.33Wave quantities
Understand the terms amplitude, frequency, period, speed and wavelength
2.3.34Wave equation
Be able to use the wave equation v = fλ
2.3.35Longitudinal waves
Be able to describe longitudinal waves in terms of pressure variation and the displacement of molecules
2.3.36Transverse waves
Be able to describe transverse waves
2.3.37Wave graphs
Be able to draw and interpret graphs representing transverse and longitudinal waves including standing/stationary waves
2.3.38Core Practical 4 - speed of sound in air
CORE PRACTICAL 4: Determine the speed of sound in air using a 2-beam oscilloscope, signal generator, speaker and microphone
2.3.39Wavefronts, coherence and interference
Know and understand what is meant by wavefront, coherence, path difference, superposition, interference and phase
2.3.40Phase difference and path difference
Be able to use the relationship between phase difference and path difference
2.3.41Standing waves, nodes and antinodes
Know what is meant by a standing or stationary wave, understand how it is formed, and identify nodes and antinodes.
2.3.42Speed of a transverse wave on a string
Use v = √(T/μ) for the speed of a transverse wave on a string.
2.3.43Core Practical 5 - vibrating string frequency
CORE PRACTICAL 5: Investigate how length, tension and mass per unit length affect the frequency of a vibrating string or wire.
2.3.44Intensity of radiation
Use I = P/A for the intensity of radiation.
2.3.45Refraction at a boundary
Use n1 sin θ1 = n2 sin θ2 at a boundary between two media and refractive index n = c/v.
2.3.46Critical angle
Calculate critical angle using sin C = 1/n.
2.3.47Total internal reflection
Be able to predict whether total internal reflection will occur at an interface
2.3.48Measuring refractive index
Understand how to measure the refractive index of a solid material
2.3.49Plane polarisation
Understand what is meant by plane polarisation
2.3.50Diffraction and Huygens’ construction
Understand what is meant by diffraction and use Huygens’ construction to explain what happens to a wave when it meets a slit or an obstacle
2.3.51Diffraction grating equation
Be able to use nλ = dsinθ for a diffraction grating
2.3.52Core Practical 6 - wavelength using diffraction grating
CORE PRACTICAL 6: Determine the wavelength of light from a laser or other light source using a diffraction grating
2.3.53Electron diffraction evidence
Understand how diffraction experiments provide evidence for the wave nature of electrons
2.3.54De Broglie wavelength
Use the de Broglie equation λ = h/p.
2.3.55Transmission and reflection at boundaries
Understand that waves can be transmitted and reflected at an interface between media
2.3.56Pulse-echo techniques
Understand how a pulse-echo technique can provide information about the position of an object and how the amount of information obtained may be limited by the wavelength of the radiation or by the duration of pulses
2.3.57Wave and photon models of EM radiation
Understand how the behaviour of electromagnetic radiation can be described in terms of a wave model and a photon model, and how these models developed over time
2.3.58Photon energy
Be able to use the equation E = hf, that relates the photon energy to the wave frequency
2.3.59Photon absorption and photoelectron emission
Understand that the absorption of a photon can result in the emission of a photoelectron
2.3.60Threshold frequency and work function
Understand threshold frequency and work function and use the photoelectric equation hf = φ + ½mvmax².
2.3.61Electronvolt
Be able to use the electronvolt (eV) to express small energies
2.3.62Photoelectric effect evidence
Understand how the photoelectric effect provides evidence for the particle nature of electromagnetic radiation
2.3.63Atomic line spectra and energy levels
Understand atomic line spectra in terms of transitions between discrete energy levels and understand how to calculate the frequency of radiation that could be emitted or absorbed in a transition between energy levels.
2.4 - Electric Circuits
2.4.64Electric current
Understand current as the rate of flow of charge and use I = ΔQ/Δt.
2.4.65Potential difference
Use potential difference V = W/Q.
2.4.66Resistance and Ohm’s law
Understand resistance R = V/I and Ohm's law as the special case I ∝ V at constant temperature.
2.4.67Current and p.d. distributions in circuits
(a) understand how the distribution of current in a circuit is a consequence of charge conservation (b) understand how the distribution of potential differences in a circuit is a consequence of energy conservation
2.4.68Combining resistances in series and parallel
Be able to derive the equations for combining resistances in series and parallel using the principles of charge and energy conservation, and be able to use these equations
2.4.69Electrical power and energy
Use P = VI and W = VIt, and derive and use P = I²R and P = V²/R.
2.4.70I-V graphs for circuit components
Sketch, recognise and interpret current–potential-difference graphs for ohmic conductors, filament bulbs, thermistors and diodes.
2.4.71Resistivity
Use R = ρl/A for the resistance of a uniform conductor.
2.4.72Core Practical 7 - electrical resistivity
CORE PRACTICAL 7: Determine the electrical resistivity of a material
2.4.73Conduction model and resistivity
Be able to use I = nqvA to explain the large range of resistivities of different materials
2.4.74Potential along a current-carrying wire
Understand how the potential along a uniform current-carrying wire varies with the distance along it
2.4.75Potential divider circuits
Understand the principles of a potential divider circuit and understand how to calculate potential differences and resistances in such a circuit
2.4.76Variable-resistance potential dividers
Be able to analyse potential divider circuits where one resistance is variable including thermistors and light dependent resistors (LDRs)
2.4.77E.m.f. and internal resistance
Know the definition of electromotive force (e.m.f.) and understand what is meant by internal resistance and know how to distinguish between e.m.f. and terminal potential difference
2.4.78Core Practical 8 - e.m.f. and internal resistance
CORE PRACTICAL 8: Determine the e.m.f. and internal resistance of an electrical cell
2.4.79Temperature effects on resistance
Understand how changes of resistance with temperature may be modelled in terms of lattice vibrations and number of conduction electrons and understand how to apply this model to metallic conductors and negative temperature coefficient thermistors
2.4.80Illumination effects on LDR resistance
Understand how changes of resistance with illumination may be modelled in terms of the number of conduction electrons and understand how to apply this model to LDRs.