Electrical Circuit
Electricity and Magnetism

Starting to understand potential difference

Physics Narrative for 11-14 Supporting Physics Teaching

Making sense of voltmeter readings using energy hills

So, the voltmeter is connected across the circuit component (battery or bulb) in order to measure the energy shifted for each coulomb of charge passing through the component. It measures the energy shifted each time one unit of charge passes through the component.

Making sense of voltmeter readings with series connections using energy hills

As before, we assume that no energy is shifted to the surroundings through the connecting wires.

So, the sum of the energies shifted by each bulb is equal to the energy shifted from the chemical store of the battery. So we have X + X is equal to 3.0 volt. So X is 1.5 volt, assuming the bulbs have equal resistances.

Making sense of voltmeter readings with parallel connections using energy hills

As before, we assume that no energy is shifted to the surroundings through the connecting wires.

So, the full battery voltage of 3 volt is dropped across each bulb. Once again, we suggest you keep the description simple, and assume that no energy is shifted to the surroundings by the connecting wires.

IOP AWARDS 2025

Teachers of Physics Awards

The Teachers of Physics Award celebrates the success of secondary school physics teachers who have raised the profile of physics and science in schools. Nominations for 2025 are now open.

Start your nomination now