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Physics Lab: Energy Stored in a Charged Capacitor
We don’t normally use a capacitor to store energy like a battery, but it’s also sort of like a battery. So, here’s what we are going to do. First, I’m going to derive an expression for the energy stored in a capacitor (without using calculus). Second, I will experimentally measure the energy in a capacitor. Here we go.
Energy Stored in a Capacitor
What is a capacitor? It’s easiest to think about a parallel plate capacitor. This is just two plates with equal and opposite charges on the plates. Here are all the details you need to know for a capacitor.
Yes, there is a constant electric field (E) inside the capacitor and the plates have an area A separated by a distance d. The magnitude of the electric field depends on the amount of charge (Q) on the plates. Because this electric field goes over some distance, there is a change in potential (V) across the plates.
Where C is the capacitance of the capacitor (in Farads). This value only depends on the physical parameters (shape and distance) of the capacitor. Note: the change in potential can be calculated as E*d ONLY because the electric field is…
