An electromagnetic wave propagates along the +y direction as shown in the figure. If the electric field at the origin is along the +z direction, what is the direction of the magnetic field?
A) +z
B) -z
C) +y
D) +x
E) -x

Question

An electromagnetic wave propagates along the +y direction as shown in the figure. If the electric field at the origin is along the +z direction, what is the direction of the magnetic field? 
A) +z 
B) -z 
C) +y 
D) +x 
E) -x

Quizplus · Accepted Answer

According to the right-hand rule, the magnetic field will be perpendicular to both the electric field and the direction of propagation. Since the electric field is in the +z direction and the wave is propagating in the +y direction, the magnetic field must be in the +x direction.

An Electromagnetic Wave Propagates Along the +Y Direction as Shown