Electricity

Used for appliances without an earth wire
Have plastic casings
Designed so that the live wire cannot touch the casing
Cannot give an electric shock

yellow and green. If the live wire becomes damaged/touches the metal casing, the earth wire can provide a low resistance path for the current to escape. The large current passes the fuse blows out and breaks the circuit

The large current passes the fuse blows out and breaks the circuit (3A 5A 13A). In a circuit breaker - the switch is opened to break the circuit. (can be reset, fuses have to be replaced and cb operate faster)

Alternating current - current continously changes direction
Direct current - current/electrons flow one way.

components can be swithced on/off indepedently
same voltage in every branch - same brightness in every branch, turning on branch on or adding more components doesn't affect the brightness of others
if one bulb breaks, the bulbs in other branches are unafffected

Current is the same everywhere, voltage is shared between the components. adding more components increases the resistance

current is directly proportional to the voltage and the resistance stays the same (the steeper the slope the smaller the R)

The resistance of the lamp changes, at higher currents and voltages the resistance increases, this is because the temperature increases, the atoms have more kinetic energy and vibrate faster, making it harder for electrons to pass through.

They have high resistance when the current is one direction and low resistance when it is in the opposite direction. Current flows one way only

Resistance decreases as light intensity increases and current increases (burglar alarms)
thermistor: resistance decreases as temp increases (fire alarms)

The wires of a heating element are designed to have high resistance (electrons collide with the ions much more) transferring thermal energy, this helps the heating element like toaster and kettle to heat up quickly without using much current
voltage, current and resistance equation
charge, current and time equation
energy transferred, charge and voltage
power, current and voltage equation

voltage = current x resistance V = IR
charge = current × time Q = It
energy transferred = charge × voltage E = Q × V
power = current x voltage P = IV
energy transferred = current x voltage x time E=IV
Current
Voltage

A flow of electric charge. A
The energy transferred per unit charge passed, the amount of energy the cell transfers to each culomb of charge flowing through it (V, J/C)
Rate at which energy is transferred

As aircraft fly through the air, the friction causes the aircraft to be charged with static electricity. After an aircraft lands, and while it is being fuelled, there is a possibility of the charges escaping to earth as a spark. But it can also ignite with the fuel causing explosion Solution: as soon as it lands, earth the plane with a conductor before refueling, allowing the built-up charge to flow to earth

Electrostatic charge build up on clouds due to friction, when the charge becomes large enough, a high voltage is created and the electrons earth in a form of lightning. Rubbing polythene rod and cloth together, e transfers from the cloth to the rod. In acetate rod e- transfers from the rod to the cloth. Use a rod of known charge to test what charge the test rod holds (repel/attract)