Question

A sinusoidal electromagnetic wave is propagating in a vacuum in the +z-direction. If at a particular instant and at a certain point in space the electric field is in the +x-direction and has a magnitude of 4.00 V/m, what is the magnitude of the magnetic field of the wave at this same point in space and instant in time?

Answer 1

B = 1.33 10⁻⁸ T , the magnetic field must be in the y + direction

Step-by-step explanation:

In an electromagnetic wave the electric and magnetic fields are in phase

c = E / B

B = E / c

let's calculate

B = 4.00 / 3 10⁸

B = 1.33 10⁻⁸ T

To determine the direction we use that the electric and magnetic fields and the speed of the wave are perpendicular.

If the wave advances in the + Z direction and the electric field is in the + x direction, the magnetic field must be in the y + direction