An electromagnetic wave is propagating towards the west in free space.At a certain moment the direction of the magnetic field vector associated with this wave points vertically upward.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 upward
E)horizontal and pointing east

Question

Quizplus · Accepted Answer

The direction of the electric field vector in an electromagnetic wave is given by the cross product of the direction of propagation and the magnetic field direction. Since the wave is propagating west and the magnetic field is upward, the electric field must be perpendicular to both, pointing south.

An Electromagnetic Wave Is Propagating Towards the West in Free