Grade 12 physics

By the end of this section you should be able to:

• Define the terms atomic mass, mole, molar mass and Avogadro’s number.

Use their relationship to solve related problems.

• Define the zeroth law of thermodynamics.

• Determine the relationship between temperature and energy transfer and

thermal equilibrium.

• State what is meant by an absolute scale of temperature.

• Draw phase diagrams to determine the triple point of a substance.

• Differentiate between the critical point and the boiling point of a

substance.

• Give the definitions of isothermal, isobaric, isochoric and adiabatic

processes and draw their associated p–V diagrams.

• Calculate work and heat for ideal gas processes.

• State the first law of thermodynamics.

• Identify the appropriate form of the first law of thermodynamics for

isobaric, isochoric and isothermal processes.

• Describe ways of changing the internal energy of a gas.

• Apply thermodynamics laws to solve simple numerical problems.

• Solve problems involving calculations of pressure, temperature or volume

for a gas undergoing adiabatic changes.

• Define molar heat capacity.

• Distinguish between molar heat capacity at constant pressure and at

constant volume. Show their relationship based on Mayer’s equation.

• Show that the molar heat capacity at constant pressure is greater than

the molar heat capacity at constant volume.

• Evaluate Cp – Cv and Cp

Cv

for an ideal gas.

• Indentify the value of Cp

Cv for atomic gases and monatomic gasses.

• Use TVγ–1 = constant for adiabatic processes to solve problems.

• State the assumptions made to define an ideal gas.

• Describe the kinetic theory of gases, including the importance of

Brownian motion and diffusion.

• Define r.m.s. velocity of a gas and the mean free path for a gas particle.

• Use the expression for the pressure of an ideal gas in terms of its

density and mean square speed of molecules to solve problems.

• Solve problems to determine p, V, T or r.m.s. speed of gas molecules for

an ideal gas, given relevant data.

• State Graham’s law of diffusion and use it to solve related problems.

• State Dalton’s law of partial pressure and use it to solve related

problems.

• State the second law of thermodynamics.

• Appreciate that the second law of thermodynamics places sharp

constraints on the maximum possible efficiency of heat engines and

refrigerators.

• Distinguish between reversible and irreversible processes.

• Define entropy as a measure of disorder and state the second law of

thermodynamics in terms of entropy.

• Describe the fundamental principles of heat engines and refrigerators.

• Solve problems involving heat flow, work and efficiency in a heat engine.

• Identify that all real heat engines lose some heat to their surrondings.

• Investigate the physical principles that all heat engines and

refrigerators must obey.

By the end of this section you should be able to:

• Describe the periodic motion of a vibrating object in qualitative

terms, and analyse it in quantitative terms (e.g. the motion of a

pendulum, a vibrating spring, a tuning fork).

• Define simple harmonic motion (SHM) and describe the

relationship between SHM and circular motion.

• Derive and use expressions for the frequency, periodic time,

displacement, velocity and acceleration of objects performing

SHM.

• Draw and analyse x–t, v–t and a–t graphs for SHM.

• Use Newton’s second law and Hooke’s law to derive ω = √k/m.

• Describe the effects: free oscillations, damping, forced oscillations

and resonance.

• Analyse the components of resonance and identify the conditions

required for resonance to occur in vibrating objects and in various

media, including the effects of damping on resonance.

• Explain the energy changes that occur when a body performs SHM.

• Draw and interpret graphs showing the variation of kinetic energy

and potential energy of an object performing SHM.

• Relate the energy of an oscillator to its amplitude.

• Solve problems on SHM involving period of vibration and energy

transfer. 

• Describe the characteristics of a mechanical wave and identify that

the speed of the wave depends on the nature of medium.

• Use the equation v = √ T/μ to solve related problems

• Describe the characteristics of a travelling wave and derive the

standard equation y = Acos(ωt + ϕ)

• Define the terms phase, phase speed and phase constant for a

travelling wave.

• Explain and graphically illustrate the principle of superposition,

and identify examples of constructive and destructive interference.

• Identify the properties of standing waves and for both mechanical

and sound waves, explain the conditions for standing waves to

occur, including definitions of the terms node and antinode.

• Derive the standing wave equations.

• Calculate the frequency of the harmonics along a string, an open

pipe and a pipe closed at one end.

• Explain the modes of vibration of strings and solve problems

involving vibrating strings.

• Explain the way air columns vibrate and solve problems involving

vibrating air columns.

• Analyse, in quantitative terms, the conditions needed for

resonance in air columns, and explain how resonance is used in a

variety of situations.

• Identify musical instruments using air columns, and explain how

different notes are produced.

• Define the intensity of sound and state the relationship between

intensity and distance from the source.

• Describe the dependence of the speed of sound on the bulk

modulus and density of the medium. Use v = √ B/ρ

• Give intensity of sound in decibels, and define the terms threshold

of pain and threshold of hearing.

• Describe the intensity level versus frequency graph to know which

the human ear is most sensitive to.

• Explain the Doppler effect, and predict in qualitative terms the

frequency change that will occur in a variety of conditions.

• Explain some practical applications of the Doppler effect.

By the end of this section you should be able to:

• Define the term wave front.

• State Huygens’s principle.

• Understand reflection and refraction of plane wave fronts

(including diagrams).

• Understand the proof of the laws of reflection and refraction using

Huygens’s principle.

• State the laws of reflection and refraction.

• Describe reflection and refraction in terms of the wave nature of

light.

• Describe the phenomena of wave interference as it applies to light

in qualitative and quantitative terms using diagrams and sketches.

• Compare the destructive and constructive interference of light with

superposition along a string.

• Identify the interference pattern produced by the diffraction of

light through narrow slits (single and double slits).

• Define an interferometer as a device which uses the interference

of two beams of light to make precise measurements of their path

difference.

• Define thin film interference and apply and use the equations to

solve problems.

• Explain the interference in Young’s double slit experiment.

• Carry out calculations involving Young’s double slit experiment.

• State the conditions necessary for the interference of light to be

shown.

• Describe the diffraction due to a single slit, including the interference

caused rays of light coming from different parts of the slit.

• Describe and explain the diffraction of light in quantitative terms

using diagrams.

• Describe the effects of using a diffraction grating.

By the end of this section you should be able to:

• Analyse, in quantitative terms, electric fields and the forces

produced by a single point charge, two point charges and two

oppositely charge parallel plates.

• Define the term electric dipole and electric dipole moment.

Describe what happens to a dipole placed inside an electric field.

• State Gauss’ law and define Gaussian surface and electric flux.

• Describe and explain in quantitative terms the electric field that

exists inside and on the surface of a charged conductor.

• Describe Millikan’s oil drop experiment.

• Apply the concept of electric potential energy to a variety of

contexts.

• Use the formula for electric potential due to an isolated point

charge.

• Apply the concepts of electrical energy to solve problems relating

to conservation of energy.

• Derive the relationship between electric field strength and

potential.

• Compare electric potential energy with gravitational potential

energy.

• Derive the formula for a parallel plate capacitor (from Gauss’ law),

including use of a dielectric.

• Define the dielectric constant.

• Explain qualitatively the charge and discharge of a capacitor in

series with a resistor.

• Explain the behaviour of an insulator in an electric field.

• Define electric energy density and derive the formula for the

energy density for an electric field using a parallel plate capacitor.

• Solve problems involving capacitances, dielectrics and energy

stored in a capacitor.

By the end of this section you should be able to:

• Define the terms resistance, resistivity, conductivity, current

density, drift velocity.

• Define the units coulomb, volt, ohm, watt, joule.

• Identify that current density is a vector quantity.

• Express drift velocity in terms of current density, number of charge

carriers per unit volume and elementary charge.

• Explain how the sources of e.m.f. produce a p.d.

• Express the relationship between e.m.f., terminal p.d. and internal

resistance.

• Analyse, in quantitative terms, circuit problems involving potential

difference, current and resistance.

• Compute the p.d. across a resistor in a circuit.

• State Kirchoff’s junction rule.

• Identify that Kirchoff’s junction rule is a consequence of the law of

conservation of charge.

• State Kirchoff’s loop rule.

• Identify that the loop rule is a consequence of the conservation of

energy.

• Use Kirchoff’s rules to solve related circuit problems.

• Identify the sign conventions appropriately in applying Kirchoff’s

rules.

• Solve problems involving network resistors.

• Describe how a galvanometer can be modified to measure a wide

range of currents and potential differences.

• Describe how shunt resistors are used to measure a wide range of

currents and p.d.

• Calculate shunt and multiplier values for use with a meter to give

different current and voltage ranges.

• Solve problems in which a meter resistance is involved.

• Identify and appropriately use equipment for measuring potential

difference, electrical current and resistance (e.g. use multimeters

and a galvanometer to make various measurements in an electrical

circuit, use an oscilloscope to show the characteristics of the

electrical current).

• Explain the principle of the Wheatstone bridge and solve problems

involving it.

• Explain the principle of the potentiometer and how it can be used

for measurement of e.m.f., p.d., resistance and current.

• Solve problems involving potentiometer circuits.

By the end of this section you should be able to:

• Define magnetic field.

• State the properties of magnetic field lines.

• Describe the properties, including the three-dimensional nature, of

magnetic fields.

• Describe magnetic properties of matter.

• Distinguish between the terms diamagnetic, paramagnetic and

ferromagnetic materials.

• Describe the causes of the Earth’s magnetism.

• Describe the motion of a charged particle in a magnetic field.

• Identify a moving charge sets up a magnetic field.

• Use the equation F = qv x B to determine the magnitude and

direction of the force.

• Use the expression for the force on a charged particle in a

magnetic field.

• Solve problems on the motion of charged particles in electric and

magnetic fields.

• Describe the path if θ ≠ 90°.

• Describe J.J. Thompson’s experiment of charge to mass ratio.

• Determine the value of charge mass ratio for this specific

experiment.

• Derive the expression F = I(l x B).

• Use the expression for the force on a current-carrying conductor in

a magnetic field.

• Determine the magnitude and direction of torque acting on a

current loop.

• Define magnetic dipole moment.

• Describe the working mechanism of a direct motor.

• Describe and illustrate the magnetic field produced by an electric

current in along straight conductor.

• Calculate the magnetic field strength of a straight current carrying

wire.

• Analyse and predict using the right hand rule the direction of the

magnetic field produced when electric current flows through a long

straight conductor.

• State the Biot−Savart law.

• Apply and use the Biot−Savart law to determine the expression for

magnetic field strength of a current element.

• State Ampere’s law and use it in solving problems.

• Describe and illustrate the magnetic field produced in a solenoid

and predict its direction using the right hand rule.

• Determine the horizontal component of the Earth’s magnetic field

at a location.

• Resolve the horizontal and vertical components of the Earth’s

magnetic field.

• Describe how a tangent galvanometer works.

By the end of this section you should be able to:

• Define magnetic flux.

• Use ΦB = B·A = BAcos θ to solve related problems.

• use the terms induced emf, back e.m.f, magnetic flux, flux linkage,

eddy current

• Describe experiments to investigate the factors that determine the

direction and magnitude of an induced e.m.f.

• Use an expression for the induced e.m.f. in a conductor moving

through a uniform magnetic field by considering the forces on the

charges

• State the laws of electromagnetic induction

• Use the laws of electromagnetic induction which predict the

magnitude and direction of the induced e.m.f.

• Use ε = –N∆Ø

∆t to solve related problems.

• Solve problems involving calculations of the induced emf, the

induced current.

• Analyse and describe electromagnetic induction in qualitative

terms.

• Apply Lenz’s law to explain, predict and illustrate the direction of

the electric current induced by a changing magnetic field, using

the right-hand rule.

• Describe the effects of eddy currents in large pieces of conducting

materials.

• Define the terms self-inductance, L, mutual inductance, M, and

henry, H.

• State the factors that determine the magnitude of self-inductance

and mutual inductance.

• Derive an expression for the inductance of a solenoid (L = n2

sµ0A).

• Derive and use the expression for the energy stored in an inductor

(PEB = 1

2

LI2

).

• Define magnetic energy density.

• Compare direct current (d.c.) and alternating current (a.c.) in

qualitative terms.

• Derive the expression for the emf induced in a rotating coil

ε = ωNBAsinωt.

• Draw a schematic diagram for a simple a.c. generator.

• Explain the working mechanism of a generator.

• Draw a schematic diagram of a transformer.

• Derive the transformer equation V1

V2

= N1

N2

= I2

I1 from Faraday’s law.

• Explain the importance of alternating current in the transmission

of electrical energy.

• Explain what is meant by r.m.s. values.

• Apply the relationship between r.m.s. and peak values for the

current and potential difference for a sinusoidal waveform.

• Identify that the current and voltage are in phase in a resistor in

an a.c. circuit.

• Explain the behaviour of a capacitor in an a.c. circuit.

• Derive the expression for the instantaneous current and voltage in

a resistive and capacitive circuit.

• Identify that the current leads the voltage by π

2 in a capacitor in

an a.c. circuit.

• Draw phasor diagrams for resistive and capacitive circuits.

• Define capacitive reactance.

• Use the terms: r.m.s. current, r.m.s. potential difference, peak

current, peak potential difference, half cycle average current,

phase difference, phase lag, phase lead.

• Use the terms: reactance, impedance, power factor with their

correct scientific meaning.

• Define the power factor in an a.c. circuit.

• Identify that the voltage leads the current by π

2 in an inductive

circuit.

• Explain the behaviour of an inductor in an a.c. circuit.

• Derive the expression for the instantaneous current/voltage in an

inductor in an inductive circuit.

• Define inductive reactance.

• Describe the behaviour of an RL circuit.

• Describe the behaviour of an LC circuit.

• Describe the behaviour of RLC circuits.

• Derive an expression for the impedance of RLC circuits.

• Draw phasor diagrams for RLC circuits.

• Solve problems involving the magnitude and phase of current and

applied p.d. in a.c. circuits which include resistors, capacitors and

inductors.

• Show that the average power in an a.c. capacitive circuit is zero.

• Derive the expression for the average power in an a.c. inductive

circuit.

• Derive the expression for the average power in an a.c. RLC circuit.

• Distinguish between real, apparent and ideal power of an RLC

circuit.

By the end of this section you should be able to:

• Identify that black bodies absorb all electromagnetic radiation.

• Describe the photoelectric effect and its characteristics.

• Show understanding that matter has wave nature.

• Use the de Broglie equation λ = h

p to find the wavelength of a

matter particle.

• State Heisenberg’s uncertainty principle.

• Use the uncertainly principle to relate the uncertainties in position

and momentum.

• Find the uncertainty in position from the uncertainty in momentum.

• Describe Rutherford’s model of the atom.

• Describe Bohr’s model of the atom.

• Show understanding that electrons can only exist at specific

energy states, and will not be found with energies between those

levels.

• Compute the change in energy of an atom using the relation

ΔE = Ef − Ei

.

• Represent diagrammatically the structure of simple atoms.

• Use the relationship A = Z + N to explain what is meant by the

term isotope.

• Compare the charge and mass of the electron with the charge and

mass of the proton.

• Identify nuclear force is a very strong force that holds particles in

a nucleus together.

• State some important properties of the strong force.

• Show radius and mass number are related mathematically

R = (1.2 × 10−15 m)A1/3.

• State the approximate size of an atom.

• State nuclear properties.

• Explain how nuclear stability is determined by binding energy per

nucleon.

• Define the term binding energy.

• Compare graphs of stable and unstable nuclei.

• Interpret graphs of binding energy per nucleon versus mass

number.

• Associate radioactivity with nuclear instability.

• Define the term nuclear fission.

• Define the term nuclear fusion.

• Distinguish between fission and fusion.

• Show understanding that radioactivity emission occurs randomly

over space.

• Identify that the decay process is independent of conditions

outside the nucleus.

• Identify the nature of the three types of emissions from

radioactive substances.

• Distinguish between the three kinds of emissions in terms of their

nature, relative ionising effect, relative penetrating power.

• Describe the need for safety measures in handling and using

radioisotopes.

• Describe experiments to compare the range of alpha, beta and

gamma radiation in various media.

• Predict the effect of magnetic and electric fields on the motion of

alpha, beta and gamma rays.

• Name the common detectors for α−particles, β−particles and

γ−rays.

• Associate the release of energy in a nuclear reaction with a change

in mass.

• Apply quantitatively the laws of conservation of mass and energy,

using Einstein’s mass−energy equation.

• Represent and interpret nuclear reactions of the form 14

6C → 14

6N +

0

−1e (beta).

• Represent nuclear reactions in the form of equations.

• Define the term half-life.

• Work through simple problems on half-life.

• Use graphs of random decay to show that such processes have a

constant half-life.

• State the uses of radioactive isotopes.

• Discuss problems posed by nuclear waste.