Electrons, Waves and Photons

the amount of charge which passes a point when a current of one amp flows for one second

The sum of currents flowing into a point in a circuit is equal to the sum of currents leaving that point

the average displacement of the electrons along the wire per second taking into account the collisions between the electrons and the metal

approximately 10^28 electrons per cubic metre

approximately 10^23 electrons per cubic metre

significantly fewer than semi-conductors.

the electrical energy transferred to other forms per unit charge

the potential difference between two points when one joule of electrical energy is transferred per coulomb of charge

the amount of electrical energy a battery/cell transfers from other forms per unit charge passing through it

EMF is a gain in electrical energy FROM another form, a PD is a change from electrical energy TO a different form.

the ratio of potential difference across a component to the current flowing through it

the resistance of a component which requires a pd of one volt to make a current of one amp flow through it

for a conductor at a constant temperature, current is proportional to voltage.

the product of resistance and cross sectional area divided by length

the energy transformed when a one kilowatt device operates for one hour (3.6x10^6J)

the sum of the PDs in a loop of a circuit is equal to the sum of the EMFs in that loop.

the potential difference that is applied across the load (the circuit)

distance of a point on a wave from the rest position

maximum displacement of a wave

distance between identical points on consecutive waves

the time taken for one complete wave to pass a point

how far one wave lags behind another

number of waves that pass a point per unit time

the distance covered by a wave front in one second.

when a wavefront rebounds off a surface

the change in direction of a wave due to a speed change when entering a different medium

the spreading out of waves as they pass through a gap. Maximum diffraction occurs when the gap size is approximately the same as the wavelen

when (two) waves meet at a point there is a change in overall intensity

the difference in distance travelled by two waves to arrive at the same point

a point of zero motion on a standing wave

a point of maximum motion on a standing wave

the lowest frequency that will cause a standing wave to form in a system

any frequency that will cause a standing wave to form in a system.