## EMC Question of the Week: September 13, 2021

The x-component of an electric field at a given point is E_{x} = 4 V/m. The y-component of the field at that point is E_{y} = 3 V/m. There is no z-component. What is the magnitude of the electric field at that point?

- 3.5 V/m
- 4 V/m
- 5 V/m
- 7 V/m

## Answer

The correct answer is “c.” The magnitude of the field is equal to the root mean sum of its vector components. In this case,

$\left|\overrightarrow{E}\right|=\sqrt{{E}_{x}^{2}+{E}_{y}^{2}+{E}_{z}^{2}}=\sqrt{{4}^{2}+{3}^{2}}=5\text{\hspace{0.33em}}\text{V/m.}$

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