The Engineering Mindset - 19 min
CircuitBread - 7 min
Battery and power sources are made of 'stuff' which have their own internal resistance, which we call 'r'. The internal resistance of a battery or a cell is often ignored but sometimes it can't be.
Here I show what it looks like if you look inside a battery (you probably shouldn't try this at home - there could be all sorts of dangerous chemicals). I also show you how to measure internal resistance as well as how to calculate internal resistance.
A-level Physics Tutorial: 4 min
IB Physics Tutorial: 5 min
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12 minutes
Apply Ohm's Law to solve simple DC circuit problems.
Calculate the total resistance in series circuits.
Calculate the total resistance in parallel circuits.
Apply the rules for parallel and series circuits to solve problems for combination circuits.
Solve problems involving power.
Define the concept of EMF.
Explain the relationship between EMF, terminal voltage and internal resistance.
Identify EMF, terminal voltage and internal resistance from graphs.
Discuss how EMF, terminal voltage and internal resistance change as a battery ages (becomes 'flat').
Solve problems involving EMF, terminal voltage and internal resistance.
State Kirchhoff's current and voltage laws.
Apply Kirchhoff's current law to determine currents at junctions.
Apply Kirchhoff's voltage law to determine unknown EMFs, resistances and currents flowing around a circuit.