An electromagnetic wave is propagating towards the west. At a certain moment the direction of the magnetic field vector associated with this wave points vertically up. What is the direction of the electric field vector?
A) Horizontal and pointing south
B) Vertical and pointing down
C) Horizontal and pointing north
D) Vertical and pointing up
E) Horizontal and pointing east

Question

Quizplus · Accepted Answer

The direction of the electric field vector is perpendicular to both the direction of propagation and the direction of the magnetic field vector. Since the electromagnetic wave is propagating towards the west and the magnetic field vector is pointing vertically up, the electric field vector must be horizontal and pointing south.

An Electromagnetic Wave Is Propagating Towards the West