Physics | 9702

recall and use Malus’s law ( I = I0 cos2θ ) to calculate the intensity of a plane-polarised electromagnetic wave after transmission through a polarising filter or a series of polarising filters (calculation of the effect of a polarising filter on the understand and explain experiments that demonstrate: • that a changing magnetic flux can induce an e.m.f. in a circuit • that the induced e.m.f. is in such a direction as to oppose the change producing it • the factors affecting the magnitude of the understand that computed tomography (CT) scanning produces a 3D image of an internal structure by first combining multiple X-ray images taken in the same section from different angles to obtain a 2D image of the section, then repeating this process a show a qualitative understanding of frictional forces and viscous/drag forces including air resistance (no treatment of the coefficients of friction and viscosity is required, and a simple model of drag force increasing as speed increases is sufficie understand that a physical property that varies with temperature may be used for the measurement of temperature and state examples of such properties, including the density of a liquid, volume of a gas at constant pressure, resistance of a metal, e.m explain how molecular movement causes the pressure exerted by a gas and derive and use the relationship pV = 31Nm<c2>, where < c2> is the mean-square speed (a simple model considering one-dimensional collisions and then extending to three dimensions Physical quantities - understand that all physical quantities consist of a numerical magnitude and a unit Physical quantities - make reasonable estimates of physical quantities included within the syllabus SI units - recall the following SI base quantities and their units: mass (kg), length (m), time (s), current (A), temperature (K) SI units - express derived units as products or quotients of the SI base units and use the derived units for quantities listed in this syllabus as appropriate SI units - use SI base units to check the homogeneity of physical equations SI units - recall and use the following prefixes and their symbols to indicate decimal submultiples or multiples of both base and derived units: pico (p), nano (n), micro ( μ), milli (m), centi (c), deci (d), kilo (k), mega (M), giga (G), tera (T) Errors and uncertainties - understand and explain the effects of systematic errors (including zero errors) and random errors in measurements Errors and uncertainties - understand the distinction between precision and accuracy Errors and uncertainties - assess the uncertainty in a derived quantity by simple addition of absolute or percentage uncertainties Scalars and vectors - understand the difference between scalar and vector quantities and give examples of scalar and vector quantities included in the syllabus Scalars and vectors - add and subtract coplanar vectors Scalars and vectors - represent a vector as two perpendicular components Equations of motion - define and use distance, displacement, speed, velocity and acceleration Equations of motion - use graphical methods to represent distance, displacement, speed, velocity and acceleration Equations of motion - determine displacement from the area under a velocity–time graph Equations of motion - determine velocity using the gradient of a displacement–time graph Equations of motion - determine acceleration using the gradient of a velocity–time graph Equations of motion - derive, from the definitions of velocity and acceleration, equations that represent uniformly accelerated motion in a straight line Equations of motion - solve problems using equations that represent uniformly accelerated motion in a straight line, including the motion of bodies falling in a uniform gravitational field without air resistance Equations of motion - describe an experiment to determine the acceleration of free fall using a falling object Equations of motion - describe and explain motion due to a uniform velocity in one direction and a uniform acceleration in a perpendicular direction Equations of motion - Dynamics An understanding of forces from Cambridge IGCSE/O Level Physics or equivalent is assumed. Momentum and Newton’s laws of motion - understand that mass is the property of an object that resists change in motion Momentum and Newton’s laws of motion - recall F = ma and solve problems using it, understanding that acceleration and resultant force are always in the same direction Momentum and Newton’s laws of motion - define and use linear momentum as the product of mass and velocity Momentum and Newton’s laws of motion - define and use force as rate of change of momentum Momentum and Newton’s laws of motion - state and apply each of Newton’s laws of motion Momentum and Newton’s laws of motion - describe and use the concept of weight as the effect of a gravitational field on a mass and recall that the weight of an object is equal to the product of its mass and the acceleration of free fall Momentum and Newton’s laws of motion - describe and explain qualitatively the motion of objects in a uniform gravitational field with air resistance Momentum and Newton’s laws of motion - understand that objects moving against a resistive force may reach a terminal (constant) velocity Linear momentum and its conservation - state the principle of conservation of momentum Linear momentum and its conservation - apply the principle of conservation of momentum to solve simple problems, including elastic and inelastic interactions between objects in both one and two dimensions (knowledge of the concept of coefficient of restitution is not required) Linear momentum and its conservation - recall that, for an elastic collision, total kinetic energy is conserved and the relative speed of approach is equal to the relative speed of separation Linear momentum and its conservation - understand that, while momentum of a system is always conserved in interactions between objects, some change in kinetic energy may take place Linear momentum and its conservation - Forces, density and pressure Turning effects of forces - understand that the weight of an object may be taken as acting at a single point known as its centre of gravity Turning effects of forces - define and apply the moment of a force Turning effects of forces - understand that a couple is a pair of forces that acts to produce rotation only Turning effects of forces - define and apply the torque of a couple Equilibrium of forces - state and apply the principle of moments Equilibrium of forces - understand that, when there is no resultant force and no resultant torque, a system is in equilibrium Equilibrium of forces - use a vector triangle to represent coplanar forces in equilibrium Equilibrium of forces - define and use density Equilibrium of forces - define and use pressure Equilibrium of forces - derive, from the definitions of pressure and density, the equation for hydrostatic pressure ∆p = ρg∆h Equilibrium of forces - use the equation ∆p = ρg∆h Equilibrium of forces - understand that the upthrust acting on an object in a fluid is due to a difference in hydrostatic pressure Equilibrium of forces - calculate the upthrust acting on an object in a fluid using the equation F = ρgV (Archimedes’ principle) Equilibrium of forces - Work, energy and power An understanding of the forms of energy and energy transfers from Cambridge IGCSE/O Level Physics or equivalent is assumed. Energy conservation - understand the concept of work, and recall and use work done = force × displacement in the direction of the force Energy conservation - recall and apply the principle of conservation of energy Energy conservation - recall and understand that the efficiency of a system is the ratio of useful energy output from the system to the total energy input Energy conservation - use the concept of efficiency to solve problems Energy conservation - define power as work done per unit time Energy conservation - solve problems using P = W / t Energy conservation - derive P = Fv and use it to solve problems Gravitational potential energy and kinetic energy - derive, using W = Fs, the formula ∆EP = mg∆h for gravitational potential energy changes in a uniform gravitational field Gravitational potential energy and kinetic energy - recall and use the formula ∆EP = mg∆h for gravitational potential energy changes in a uniform gravitational field Gravitational potential energy and kinetic energy - derive, using the equations of motion, the formula for kinetic energy EK = 21mv2 Gravitational potential energy and kinetic energy - recall and use EK = 21mv2 Stress and strain - understand that deformation is caused by tensile or compressive forces (forces and deformations will be assumed to be in one dimension only) Stress and strain - understand and use the terms load, extension, compression and limit of proportionality Stress and strain - recall and use Hooke’s law Stress and strain - recall and use the formula for the spring constant k = F / x Stress and strain - define and use the terms stress, strain and the Young modulus Stress and strain - describe an experiment to determine the Young modulus of a metal in the form of a wire Elastic and plastic behaviour - understand and use the terms elastic deformation, plastic deformation and elastic limit Elastic and plastic behaviour - understand that the area under the force–extension graph represents the work done Elastic and plastic behaviour - determine the elastic potential energy of a material deformed within its limit of proportionality from the area under the force–extension graph Elastic and plastic behaviour - recall and use EP = 21 Fx = 21 kx2 for a material deformed within its limit of proportionality Elastic and plastic behaviour - Waves An understanding of colour from Cambridge IGCSE/O Level Physics or equivalent is assumed. Progressive waves - describe what is meant by wave motion as illustrated by vibration in ropes, springs and ripple tanks Progressive waves - understand and use the terms displacement, amplitude, phase difference, period, frequency, wavelength and speed Progressive waves - understand the use of the time-base and y-gain of a cathode-ray oscilloscope (CRO) to determine frequency and amplitude Progressive waves - derive, using the definitions of speed, frequency and wavelength, the wave equation v = f λ Progressive waves - recall and use v = f λ Progressive waves - understand that energy is transferred by a progressive wave Progressive waves - recall and use intensity = power/area and intensity ∝ (amplitude )2 for a progressive wave Progressive waves - compare transverse and longitudinal waves Progressive waves - analyse and interpret graphical representations of transverse and longitudinal waves Doppler effect for sound waves - understand that when a source of sound waves moves relative to a stationary observer, the observed frequency is different from the source frequency (understanding of the Doppler effect for a stationary source and a moving observer is not required) Doppler effect for sound waves - use the expression fο = f sv / (v ± vs) for the observed frequency when a source of sound waves moves relative to a stationary observer Electromagnetic spectrum - state that all electromagnetic waves are transverse waves that travel with the same speed c in free space Electromagnetic spectrum - recall the approximate range of wavelengths in free space of the principal regions of the electromagnetic spectrum from radio waves to γ-rays Electromagnetic spectrum - recall that wavelengths in the range 400–700 nm in free space are visible to the human eye Polarisation - understand that polarisation is a phenomenon associated with transverse waves Stationary waves - explain and use the principle of superposition Stationary waves - show an understanding of experiments that demonstrate stationary waves using microwaves, stretched strings and air columns (it will be assumed that end corrections are negligible; knowledge of the concept of end corrections is not required) Stationary waves - explain the formation of a stationary wave using a graphical method, and identify nodes and antinodes Stationary waves - understand how wavelength may be determined from the positions of nodes or antinodes of a stationary wave Diffraction - explain the meaning of the term diffraction Diffraction - show an understanding of experiments that demonstrate diffraction including the qualitative effect of the gap width relative to the wavelength of the wave; for example diffraction of water waves in a ripple tank Interference - understand the terms interference and coherence Interference - show an understanding of experiments that demonstrate two-source interference using water waves in a ripple tank, sound, light and microwaves Interference - understand the conditions required if two-source interference fringes are to be observed Interference - recall and use λ = ax / D for double-slit interference using light The diffraction grating - recall and use d sin θ = nλ The diffraction grating - describe the use of a diffraction grating to determine the wavelength of light (the structure and use of the spectrometer are not included) Electric current - understand that an electric current is a flow of charge carriers Electric current - understand that the charge on charge carriers is quantised Electric current - recall and use Q = It Electric current - use, for a current-carrying conductor, the expression I = Anvq , where n is the number density of charge carriers Potential difference and power - define the potential difference across a component as the energy transferred per unit charge Potential difference and power - recall and use V = W / Q Potential difference and power - recall and use P = VI, P = I 2R and P = V 2 / R Resistance and resistivity - define resistance Resistance and resistivity - recall and use V = IR Resistance and resistivity - sketch the I–V characteristics of a metallic conductor at constant temperature, a semiconductor diode and a filament lamp Resistance and resistivity - explain that the resistance of a filament lamp increases as current increases because its temperature increases Resistance and resistivity - state Ohm’s law Resistance and resistivity - recall and use R = ρL / A Resistance and resistivity - understand that the resistance of a light-dependent resistor (LDR) decreases as the light intensity increases Resistance and resistivity - understand that the resistance of a thermistor decreases as the temperature increases (it will be assumed that thermistors have a negative temperature coefficient) Practical circuits - recall and use the circuit symbols shown in section 6 of this syllabus Practical circuits - draw and interpret circuit diagrams containing the circuit symbols shown in section 6 of this syllabus Practical circuits - define and use the electromotive force (e.m.f.) of a source as energy transferred per unit charge in driving charge around a complete circuit Practical circuits - distinguish between e.m.f. and potential difference (p.d.) in terms of energy considerations Practical circuits - understand the effects of the internal resistance of a source of e.m.f. on the terminal potential difference Kirchhoff’s laws - recall Kirchhoff’s first law and understand that it is a consequence of conservation of charge Kirchhoff’s laws - recall Kirchhoff’s second law and understand that it is a consequence of conservation of energy Kirchhoff’s laws - derive, using Kirchhoff’s laws, a formula for the combined resistance of two or more resistors in series Kirchhoff’s laws - use the formula for the combined resistance of two or more resistors in series Kirchhoff’s laws - derive, using Kirchhoff’s laws, a formula for the combined resistance of two or more resistors in parallel Kirchhoff’s laws - use the formula for the combined resistance of two or more resistors in parallel Kirchhoff’s laws - use Kirchhoff’s laws to solve simple circuit problems Potential dividers - understand the principle of a potential divider circuit Potential dividers - recall and use the principle of the potentiometer as a means of comparing potential differences Potential dividers - understand the use of a galvanometer in null methods Potential dividers - explain the use of thermistors and light-dependent resistors in potential dividers to provide a potential difference that is dependent on temperature and light intensity Atoms, nuclei and radiation - infer from the results of the α-particle scattering experiment the existence and small size of the nucleus Atoms, nuclei and radiation - describe a simple model for the nuclear atom to include protons, neutrons and orbital electrons Atoms, nuclei and radiation - distinguish between nucleon number and proton number Atoms, nuclei and radiation - understand that isotopes are forms of the same element with different numbers of neutrons in their nuclei Atoms, nuclei and radiation - understand and use the notation A Z X for the representation of nuclides Atoms, nuclei and radiation - understand that nucleon number and charge are conserved in nuclear processes Atoms, nuclei and radiation - describe the composition, mass and charge of α-, β- and γ-radiations (both β– (electrons) and β+ (positrons) are included) Atoms, nuclei and radiation - understand that an antiparticle has the same mass but opposite charge to the corresponding particle, and that a positron is the antiparticle of an electron Atoms, nuclei and radiation - state that (electron) antineutrinos are produced during β– decay and (electron) neutrinos are produced during β+ decay Atoms, nuclei and radiation - understand that α-particles have discrete energies but that β-particles have a continuous range of energies because (anti)neutrinos are emitted in β-decay Atoms, nuclei and radiation - represent α- and β-decay by a radioactive decay equation of the form UT h92238 90234 Atoms, nuclei and radiation - use the unified atomic mass unit (u) as a unit of mass Fundamental particles - understand that a quark is a fundamental particle and that there are six flavours (types) of quark: up, down, strange, charm, top and bottom Fundamental particles - recall and use the charge of each flavour of quark and understand that its respective antiquark has the opposite charge (no knowledge of any other properties of quarks is required) Fundamental particles - recall that protons and neutrons are not fundamental particles and describe protons and neutrons in terms of their quark composition Fundamental particles - understand that a hadron may be either a baryon (consisting of three quarks) or a meson (consisting of one quark and one antiquark) Fundamental particles - describe the changes to quark composition that take place during β– and β+ decay Fundamental particles - recall that electrons and neutrinos are fundamental particles called leptons Kinematics of uniform circular motion - define the radian and express angular displacement in radians Kinematics of uniform circular motion - understand and use the concept of angular speed Kinematics of uniform circular motion - recall and use ω = 2π / T and v = rω Centripetal acceleration - understand that a force of constant magnitude that is always perpendicular to the direction of motion causes centripetal acceleration Centripetal acceleration - understand that centripetal acceleration causes circular motion with a constant angular speed Centripetal acceleration - recall and use a = rω2 and a = v2 / r Centripetal acceleration - recall and use F = mrω2 and F = mv2 / r Centripetal acceleration - Gravitational fields Gravitational field - understand that a gravitational field is an example of a field of force and define gravitational field as force per unit mass Gravitational field - represent a gravitational field by means of field lines Gravitational force between point masses - understand that, for a point outside a uniform sphere, the mass of the sphere may be considered to be a point mass at its centre Gravitational force between point masses - recall and use Newton’s law of gravitation F = Gm1m2 / r2 for the force between two point masses Gravitational force between point masses - analyse circular orbits in gravitational fields by relating the gravitational force to the centripetal acceleration it causes Gravitational force between point masses - understand that a satellite in a geostationary orbit remains at the same point above the Earth’s surface, with an orbital period of 24 hours, orbiting from west to east, directly above the Equator Gravitational force between point masses - derive, from Newton’s law of gravitation and the definition of gravitational field, the equation g = GM / r 2 for the gravitational field strength due to a point mass Gravitational force between point masses - recall and use g = GM / r Gravitational force between point masses - understand why g is approximately constant for small changes in height near the Earth’s surface Gravitational potential - define gravitational potential at a point as the work done per unit mass in bringing a small test mass from infinity to the point Gravitational potential - use ϕ = –GM / r for the gravitational potential in the field due to a point mass Gravitational potential - understand how the concept of gravitational potential leads to the gravitational potential energy of two point masses and use EP = –GMm / r Gravitational potential - Temperature Thermal equilibrium - understand that (thermal) energy is transferred from a region of higher temperature to a region of lower temperature Thermal equilibrium - understand that regions of equal temperature are in thermal equilibrium Temperature scales - understand that the scale of thermodynamic temperature does not depend on the property of any particular substance Temperature scales - convert temperatures between kelvin and degrees Celsius and recall that T / K = θ / °C + 273. Temperature scales - understand that the lowest possible temperature is zero kelvin on the thermodynamic temperature scale and that this is known as absolute zero Temperature scales - define and use specific heat capacity Temperature scales - define and use specific latent heat and distinguish between specific latent heat of fusion and specific latent heat of vaporisation Temperature scales - Ideal gases The mole - understand that amount of substance is an SI base quantity with the base unit mol The mole - use molar quantities where one mole of any substance is the amount containing a number of particles of that substance equal to the Avogadro constant NA Equation of state - understand that a gas obeying pV ∝ T, where T is the thermodynamic temperature, is known as an ideal gas Equation of state - recall and use the equation of state for an ideal gas expressed as pV = nRT, where n = amount of substance (number of moles) and as pV = NkT, where N = number of molecules Equation of state - recall that the Boltzmann constant k is given by k = R / NA Kinetic theory of gases - state the basic assumptions of the kinetic theory of gases Kinetic theory of gases - understand that the root-mean-square speed cr.m.s. is given by c<> Kinetic theory of gases - compare pV = 31Nm<c2> with pV = NkT to deduce that the average translational kinetic energy of a molecule is 23 kT, and recall and use this expression Internal energy - understand that internal energy is determined by the state of the system and that it can be expressed as the sum of a random distribution of kinetic and potential energies associated with the molecules of a system Internal energy - relate a rise in temperature of an object to an increase in its internal energy The first law of thermodynamics - recall and use W = p∆V for the work done when the volume of a gas changes at constant pressure and understand the difference between the work done by the gas and the work done on the gas The first law of thermodynamics - recall and use the first law of thermodynamics ∆U = q + W expressed in terms of the increase in internal energy, the heating of the system (energy transferred to the system by heating) and the work done on the system The first law of thermodynamics - Oscillations Simple harmonic oscillations - understand and use the terms displacement, amplitude, period, frequency, angular frequency and phase difference in the context of oscillations, and express the period in terms of both frequency and angular frequency Simple harmonic oscillations - understand that simple harmonic motion occurs when acceleration is proportional to displacement from a fixed point and in the opposite direction Simple harmonic oscillations - use a = –ω2x and recall and use, as a solution to this equation, x = x0 sin ωt Simple harmonic oscillations - use the equations v = v0 cos ωt and v = ± ω ()xx022− Simple harmonic oscillations - analyse and interpret graphical representations of the variations of displacement, velocity and acceleration for simple harmonic motion Simple harmonic oscillations - describe the interchange between kinetic and potential energy during simple harmonic motion Simple harmonic oscillations - recall and use E = 21mω2x02 for the total energy of a system undergoing simple harmonic motion Damped and forced oscillations, resonance - understand that a resistive force acting on an oscillating system causes damping Damped and forced oscillations, resonance - understand and use the terms light, critical and heavy damping and sketch displacement–time graphs illustrating these types of damping Damped and forced oscillations, resonance - understand that resonance involves a maximum amplitude of oscillations and that this occurs when an oscillating system is forced to oscillate at its natural frequency Damped and forced oscillations, resonance - Electric fields Electric fields and field lines - understand that an electric field is an example of a field of force and define electric field as force per unit positive charge Electric fields and field lines - recall and use F = qE for the force on a charge in an electric field Electric fields and field lines - represent an electric field by means of field lines Uniform electric fields - recall and use E = ∆V / ∆d to calculate the field strength of the uniform field between charged parallel plates Uniform electric fields - describe the effect of a uniform electric field on the motion of charged particles Uniform electric fields - understand that, for a point outside a spherical conductor, the charge on the sphere may be considered to be a point charge at its centre Uniform electric fields - recall and use Coulomb’s law F = Q1Q2 / (4πε0 r 2) for the force between two point charges in free space Electric field of a point charge - recall and use E = Q / (4πε0 r 2) for the electric field strength due to a point charge in free space Electric potential - define electric potential at a point as the work done per unit positive charge in bringing a small test charge from infinity to the point Electric potential - recall and use the fact that the electric field at a point is equal to the negative of potential gradient at that point Electric potential - use V = Q / (4πε0r) for the electric potential in the field due to a point charge Electric potential - understand how the concept of electric potential leads to the electric potential energy of two point charges and use EP = Qq / (4πε0 r) Electric potential - Capacitance Capacitors and capacitance - define capacitance, as applied to both isolated spherical conductors and to parallel plate capacitors Capacitors and capacitance - recall and use C = Q / V Capacitors and capacitance - derive, using C = Q / V, formulae for the combined capacitance of capacitors in series and in parallel Capacitors and capacitance - use the capacitance formulae for capacitors in series and in parallel Capacitors and capacitance - determine the electric potential energy stored in a capacitor from the area under the potential–charge graph Capacitors and capacitance - recall and use W = 21QV = 21CV2 Discharging a capacitor - analyse graphs of the variation with time of potential difference, charge and current for a capacitor discharging through a resistor Discharging a capacitor - recall and use τ = RC for the time constant for a capacitor discharging through a resistor Discharging a capacitor - use equations of the form x = x0 e–(t / RC) where x could represent current, charge or potential difference for a capacitor discharging through a resistor Discharging a capacitor - Magnetic fields Concept of a magnetic field - understand that a magnetic field is an example of a field of force produced either by moving charges or by permanent magnets Concept of a magnetic field - represent a magnetic field by field lines Force on a current-carrying conductor - understand that a force might act on a current-carrying conductor placed in a magnetic field Force on a current-carrying conductor - recall and use the equation F = BIL sin θ, with directions as interpreted by Fleming’s left-hand rule Force on a current-carrying conductor - define magnetic flux density as the force acting per unit current per unit length on a wire placed at right- angles to the magnetic field Force on a current-carrying conductor - determine the direction of the force on a charge moving in a magnetic field Force on a current-carrying conductor - recall and use F = BQv sin θ Force on a current-carrying conductor - understand the origin of the Hall voltage and derive and use the expression VH = BI / (ntq), where t = thickness Force on a current-carrying conductor - understand the use of a Hall probe to measure magnetic flux density Force on a current-carrying conductor - describe the motion of a charged particle moving in a uniform magnetic field perpendicular to the direction of motion of the particle Force on a current-carrying conductor - explain how electric and magnetic fields can be used in velocity selection Magnetic fields due to currents - sketch magnetic field patterns due to the currents in a long straight wire, a flat circular coil and a long solenoid Magnetic fields due to currents - understand that the magnetic field due to the current in a solenoid is increased by a ferrous core Magnetic fields due to currents - explain the origin of the forces between current-carrying conductors and determine the direction of the forces Electromagnetic induction - define magnetic flux as the product of the magnetic flux density and the cross-sectional area perpendicular to the direction of the magnetic flux density Electromagnetic induction - recall and use Φ = BA Electromagnetic induction - understand and use the concept of magnetic flux linkage Electromagnetic induction - recall and use Faraday’s and Lenz’s laws of electromagnetic induction Characteristics of alternating currents - understand and use the terms period, frequency and peak value as applied to an alternating current or voltage Characteristics of alternating currents - use equations of the form x = x0 sin ωt representing a sinusoidally alternating current or voltage Characteristics of alternating currents - recall and use the fact that the mean power in a resistive load is half the maximum power for a sinusoidal alternating current Characteristics of alternating currents - distinguish between root-mean-square (r.m.s.) and peak values and recall and use I r.m.s. = I0 / 2 and Vr.m.s. = V0 / 2 for a sinusoidal alternating current Rectification and smoothing - distinguish graphically between half-wave and full-wave rectification Rectification and smoothing - explain the use of a single diode for the half-wave rectification of an alternating current Rectification and smoothing - explain the use of four diodes (bridge rectifier) for the full-wave rectification of an alternating current Rectification and smoothing - analyse the effect of a single capacitor in smoothing, including the effect of the values of capacitance and the load resistance Rectification and smoothing - Quantum physics Energy and momentum of a photon - understand that electromagnetic radiation has a particulate nature Energy and momentum of a photon - understand that a photon is a quantum of electromagnetic energy Energy and momentum of a photon - recall and use E = hf Energy and momentum of a photon - use the electronvolt (eV) as a unit of energy Energy and momentum of a photon - understand that a photon has momentum and that the momentum is given by p = E / c Energy and momentum of a photon - understand that photoelectrons may be emitted from a metal surface when it is illuminated by electromagnetic radiation Energy and momentum of a photon - understand and use the terms threshold frequency and threshold wavelength Energy and momentum of a photon - explain photoelectric emission in terms of photon energy and work function energy Energy and momentum of a photon - recall and use hf = Φ + 21mvmax2 Energy and momentum of a photon - explain why the maximum kinetic energy of photoelectrons is independent of intensity, whereas the photoelectric current is proportional to intensity Wave-particle duality - understand that the photoelectric effect provides evidence for a particulate nature of electromagnetic radiation while phenomena such as interference and diffraction provide evidence for a wave nature Wave-particle duality - describe and interpret qualitatively the evidence provided by electron diffraction for the wave nature of particles Wave-particle duality - understand the de Broglie wavelength as the wavelength associated with a moving particle Wave-particle duality - recall and use λ = h / p Energy levels in atoms and line spectra - understand that there are discrete electron energy levels in isolated atoms (e.g. atomic hydrogen) Energy levels in atoms and line spectra - understand the appearance and formation of emission and absorption line spectra Energy levels in atoms and line spectra - recall and use hf = E1 – E2 Mass defect and nuclear binding energy - understand the equivalence between energy and mass as represented by E = mc2 and recall and use this equation Mass defect and nuclear binding energy - represent simple nuclear reactions by nuclear equations of the form NH eO H714 24 817 11" ++ Mass defect and nuclear binding energy - define and use the terms mass defect and binding energy Mass defect and nuclear binding energy - sketch the variation of binding energy per nucleon with nucleon number Mass defect and nuclear binding energy - explain what is meant by nuclear fusion and nuclear fission Mass defect and nuclear binding energy - explain the relevance of binding energy per nucleon to nuclear reactions, including nuclear fusion and nuclear fission Mass defect and nuclear binding energy - calculate the energy released in nuclear reactions using E = c2∆m Radioactive decay - understand that fluctuations in count rate provide evidence for the random nature of radioactive decay Radioactive decay - understand that radioactive decay is both spontaneous and random Radioactive decay - define activity and decay constant, and recall and use A = λN Radioactive decay - define half-life Radioactive decay - use λ = 0.693 / t Radioactive decay - understand the exponential nature of radioactive decay, and sketch and use the relationship x = x0e–λt, where x could represent activity, number of undecayed nuclei or received count rate Production and use of ultrasound - understand that a piezo-electric crystal changes shape when a p.d. is applied across it and that the crystal generates an e.m.f. when its shape changes Production and use of ultrasound - understand how ultrasound waves are generated and detected by a piezoelectric transducer Production and use of ultrasound - understand how the reflection of pulses of ultrasound at boundaries between tissues can be used to obtain diagnostic information about internal structures Production and use of ultrasound - define the specific acoustic impedance of a medium as Z = ρc, where c is the speed of sound in the medium Production and use of ultrasound - use IR / I0 = (Z1 – Z2)2 / (Z1 + Z2)2 for the intensity reflection coefficient of a boundary between two media Production and use of ultrasound - recall and use I = I0e–μx for the attenuation of ultrasound in matter Production and use of X-rays - explain that X-rays are produced by electron bombardment of a metal target and calculate the minimum wavelength of X-rays produced from the accelerating p.d. Production and use of X-rays - understand the use of X-rays in imaging internal body structures, including an understanding of the term contrast in X-ray imaging Production and use of X-rays - recall and use I = I0e–μx for the attenuation of X-rays in matter Production and use of X-rays - understand that a tracer is a substance containing radioactive nuclei that can be introduced into the body and is then absorbed by the tissue being studied Production and use of X-rays - recall that a tracer that decays by β+ decay is used in positron emission tomography (PET scanning) Production and use of X-rays - understand that annihilation occurs when a particle interacts with its antiparticle and that mass–energy and momentum are conserved in the process Production and use of X-rays - explain that, in PET scanning, positrons emitted by the decay of the tracer annihilate when they interact with electrons in the tissue, producing a pair of gamma-ray photons travelling in opposite directions Production and use of X-rays - calculate the energy of the gamma-ray photons emitted during the annihilation of an electron-positron pair Production and use of X-rays - understand that the gamma-ray photons from an annihilation event travel outside the body and can be detected, and an image of the tracer concentration in the tissue can be created by processing the arrival times of the gamma-ray photons Production and use of X-rays - Astronomy and cosmology Standard candles - understand the term luminosity as the total power of radiation emitted by a star Standard candles - recall and use the inverse square law for radiant flux intensity F in terms of the luminosity L of the source F = L / (4πd 2) Standard candles - understand that an object of known luminosity is called a standard candle Standard candles - understand the use of standard candles to determine distances to galaxies Stellar radii - recall and use Wien’s displacement law λmax ∝ 1 / T to estimate the peak surface temperature of a star Stellar radii - use the Stefan–Boltzmann law L = 4πσr 2 T Stellar radii - use Wien’s displacement law and the Stefan–Boltzmann law to estimate the radius of a star Stellar radii - understand that the lines in the emission and absorption spectra from distant objects show an increase in wavelength from their known values Stellar radii - use ∆λ / λ . ∆f / f . v / c for the redshift of electromagnetic radiation from a source moving relative to an observer Stellar radii - explain why redshift leads to the idea that the Universe is expanding Stellar radii - recall and use Hubble’s law v . H0d and explain how this leads to the Big Bang theory (candidates will only be required to use SI units)