Physics - electricity and circuits (10,11)

current

the flow of electric charge, measured in amps

potential difference / voltage

the difference in potential energy per unit charge between two points in a circuit, measured in volts

Ohm’s law

V = IR, voltage = current x resistance

resistance

how much an object resists the flow of current, measured in ohms

series circuit

all components are connected in one loop. Current is the same throughout it.

parallel circuit

connected across parallel branches, so that the current can flow through each branch independently. The voltage across each component is the same

how to calculate total resistance in a series circuit

sum of all individual resistances

how to calculate total resistance in parallel circuit

1/Rtotal = 1/R1 + 1/R2 + …

formula for power

P = IV, power = current x voltage

static electricity

the buildup of electric charge on the surface of objects, usually caused by friction

what causes an object to become electrically charged

when it gains or loses electrons

charging by friction

two objects are rubbed together, causing the electrons to transfer from one object to another. One object becomes positively charged while the other becomes negatively charged.

color of live wire

brown

color of earth wire

green yellow

color of neutral wire

blue

alternating current / AC

a type of electrical current where the flow of charge periodically reverses direction

direct current / DC

a type of electrical current where the flow of charge always moves in the same direction

IV graph of a resistor

straight line which passes through the origin

IV graph of a bulb

curves upward because as the current increases, the resistance increases

IV graph of a diode

zero current in reverse direction as component does not work in reverse, and current only increases after voltage reaches a threshold

IV graph of LDR

straight line but changes gradient based on intensity of light