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Units
tesla – SI unit for magnetic flux density; equivalent to 1 newton per ampere per metre
weber – SI unit for magnetic flux
farad – coulomb per volt
parsec – distance that gives a parallax angle of 1 arcsecond
Quantities
electric field strength – force per unit positive charge
magnetic flux density – 
magnetic flux – magnetic flux density x area (perpendicular to field direction)
magnetic flux linkage – magnetic flux x the number of turns
capacitance – charge per unit potential difference
time constant of a circuit – time taken for current/charge/voltage of a discharging capacitor to fall to 37% of its original value (equal to the product of capacitance and resistance
proton number – number of protons in the nucleus of an atom (a.k.a. atomic number)
nucleon number – number of neutrons and protons in the nucleus of an atom (a.k.a. mass number)
activity – the rate of decay of nuclei in a radioactive sample
decay constant – probability of a decay of a nucleus per unit time
half life – the mean time taken for half the number of active nuclei in a radioactive sample to decay
binding energy – minimum energy to separate protons and neutrons of a nucleus
intensity – power per unit cross-sectional area
Concepts
Faraday’s law of electromagnetic induction – induced e.m.f. is proportional to the rate of change of magnetic flux
Lenz’s law – the induced current or e.m.f. is in a direction so as to produce effects which oppose the change producing it
isotope – a version of an element with a different number of neutrons (but the same number of protons and electrons)
Doppler effect – the change in the frequency and wavelength of a wave caused by the relative movement between source and detector
piezoelectric effect – application of a p.d. across a crystal causes a vibration
Compton effect – x-ray photon interacts with electron; the scattered photon has a longer wavelength and the electron is ejected
Olber’s paradox – if Universe is static and infinite, the night sky should be uniformly bright because every line of sight would end on a star
Hubble’s law – the speed of recession of a galaxy is proportional to its distance
cosmological principle – universe has the same large-scale structure when observed from any point (homogenous, isotropic and the laws of physics are universal
3K microwave background radiation – gamma radiation released during the Big Bang has stretched as the Universe expanded, causing it to become microwave with an energy equivalent to a temperature of 3K
critical density – the density for which the universe will expand towards a finite limit (resulting in a flat universe)
open universe – universe will expand forever
flat universe – universe will expand towards a finite limit
closed universe – universe will contract (to a big crunch)
nature of radioactive decay:
- random – cannot predict when or which nucleus will decay next
- spontaneous – decay cannot be induced
nature and range of fundamental forces acting on nucleons:
- electrostatic force – repulsive between protons, no effect on neutrons; long-ranged
- gravitational force – attractive; long-ranged
- strong nuclear force – attractive; short-ranged
principals of positron emission tomography (PET):
- a positron emitting tracer is used
- positron annihilates with an electron inside the patient
- this produces two gamma photons travelling in opposite directions
- patient is surrounded by a ring of gamma detectors
- arrival times of photons indicates location of tumour
- 3D image is created by a computer
principals of a CAT scan:
- x-ray beam passes through patient at different angles, using a thin fan-shaped beam
- images of ‘slices’ through patient are produced by a computer
- x-ray tube moves along the patient
- produces 3D image and provides better contrast between different soft tissues than a conventional x-ray
principals of ultrasound scanning:
- a piezoelectric crystal is used to send pulses of ultrasound into the patient
- ultrasound waves are reflected at boundaries of tissue
- the intensity of the reflected signal depends on the acoustic impedances
- the time delay is used to determine the depth
principles of magnetic resonance:
- some nuclei behave as small magnets when placed in a strong magnetic field
- the frequency of precession is know as Lamor frequency
- radio frequency pulses are applied which produce resonance
- when radio frequency pulse is turned off, nuclei relax and emit RF signal
- RF signal is detected by a coil receiver and processed
- the magnetic field is non-uniform to locate position of the nuclei in body
- different tissues have different relaxation times for the hydrogen nuclei
formation of a star:
- gas cloud drawn together by gravitational forces (gravitational collapse)
- GPE is converted to KE, causing temperature to increase
- hydrogen nuclei (protons) fuse to make helium + energy
- a stable star is formed when the radiation pressure is equal to the gravitational pressure
probable evolution of the Sun:
- when hydrogen runs out, the outer layers of the star expand
- a red giant is formed
- the outer layers are shed, leaving behind a white dwarf
probable evolution of a star much more massive than the Sun:
- supernova
- core becomes either a neutron star or black hole
evolution of universe from 
seconds after the Big Bang to the present:
- hot, dense singularity
- all forces were unified
- expansion led to cooling
- quark and lepton soup
- more matter than antimatter
- quarks combine to form hadrons (protons and neutrons)
- helium formed from imbalance of protons and neutrons
- atoms formed
- gravitational force forms stars/galaxies
- temperature becomes 2.7K and the universe is saturated with microwave background radiation
evidence for the Big Bang:
- spectra from galaxies show shift to longer wavelengths (redshift), which suggests galaxies are moving away from Earth
- the more distant galaxies are moving faster
- existence of microwave background radiation; the temperature of the universe is 3K; gamma radiation stretched to become microwaves as the Universe expanded
- existence of primordial helium
- temperature fluctuations are predicted and observed