EMC Question of the Week: September 13, 2021

three-axis electric field probe

The x-component of an electric field at a given point is Ex = 4 V/m. The y-component of the field at that point is Ey = 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


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

E = E x 2 + E y 2 + E z 2 = 4 2 + 3 2 = 5 V/m.

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