Magnitude of the electric field due to a point charge (16-4)

Question 1 of 4

Question

Magnitude of the electric field due to a point charge $Q$

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Question

Absolute value of charge $Q$

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Question

Distance between point charge $Q$ and the location where the field is measured

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Review

We can use Coulomb’s law, Equation 16-1, to write an expression for the magnitude of the electric field due to a point charge $Q$ . If we place a test charge $q$ a distance $r$ from charge $Q$ , Equation 16-1 tells us that the magnitude of the Coulomb force on $q$ is $F = k\left|q\right|\left|Q\right|r^2$ . From Equation 16-2, we can also write this force magnitude as $F = \left|q\right|E$ , where $E$ is the magnitude of the electric field due to charge $Q$ at the position of test charge $q$ . Setting these two expressions for $F$ equal to each other, we get

$\left|q\right|E = \frac{k\left|q\right|\left|Q\right|}{r^2}$