Suppose we forced each truck, electron, to carry energy through two light globes as pictured on the right. The energy is now shared amongst the light globes. Each light globe gets a share of the energy. At the end of its journey each truck has no more energy.

Notice how trucks entering the first light globe carry 6 bags of energy while the trucks leaving the light globe have only three. There is a difference of 3 bags of energy. We say there is a potential difference of 3 volts across the terminals of the light globe. Click to see a different explanation for Potential difference.

The animation on the right shows another way of connecting two light globes.

What is the potential difference across the terminals of each light globe? Explain your answer.
What is the potential difference across the terminals of the battery? Explain your answer.

Look at the animation on the right. Is the number of electrons leaving the battery the same as the number of electrons passing through each light globe? Solution

Ammeters are connected along the circuit to measure current. Click to hide solution

How does this compare with the circuit above?
In which circuit will a new 6volt battery last the longest? Explain.