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? 

1. 3.5 V/m
2. 4 V/m
3. 5 V/m
4. 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,

$\left|\overrightarrow{E}\right|=\sqrt{E_x^2+E_y^2+E_z^2}=\sqrt{4^2+3^2}=5\text{V/m.}$

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