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Learning Introductory Physics with Activities

Section 9.19 Determining E from V

Exercises Warm-Up Activity

1.

Given the equation you learned about in the previous section, Principle 9.18.1, suppose you instead knew the electric potential (\(V\)), and you wanted to figure out the electric field (\(\vec{E}\)). What mathematical operation could you perform on \(V\) to get \(\vec{E}\text{?}\)
Now you have seen how we can go back and forth between \(V\) and \(\vec{E}\text{.}\) To find \(V\) from \(\vec{E}\text{,}\) you can take a derivative!

Definition 9.19.1. Electric Field: \(\vec{E}\) from V.

The electric field can be directly calculated given a known electric potential using the equation
\begin{equation*} \vec{\mathit{E}} = -\vec{\nabla}\mathit{V} \end{equation*}