An electromagnetic wave is propagating towards the west in a vacuum.At a certain moment the direction of the $\vec { B }$ field vector associated with this wave points vertically upward.What is the direction of the $\vec { E }$ field vector?
A)horizontal and pointing south
B)vertical and pointing down
C)horizontal and pointing north
D)vertical and pointing upward
E)horizontal and pointing east

Question

Quizplus · Accepted Answer

In an electromagnetic wave, the electric field ($\vec { E }$), magnetic field ($\vec { B }$), and direction of propagation are all perpendicular to each other. Given that the wave is propagating west and the magnetic field points upward, the electric field must be horizontal and perpendicular to both, which means it points south.

An Electromagnetic Wave Is Propagating Towards the West in a Vacuum.At