FIGURE 25-1
-An electromagnetic wave propagates along the +y direction as shown in Figure 25-1. If the E-field at the origin is along the +z direction, what is the direction of the B-field?
A) +z
B) -z
C) +y
D) +x
E) -x

Question

FIGURE 25-1 
-An electromagnetic wave propagates along the +y direction as shown in Figure 25-1. If the E-field at the origin is along the +z direction, what is the direction of the B-field?
A) +z 
B) -z 
C) +y 
D) +x 
E) -x

Quizplus · Accepted Answer

The right-hand rule of electromagnetism tells us that the B-field direction is perpendicular to both the direction of propagation (+y direction) and the direction of the E-field (+z direction), so it must be in the +x direction.

FIGURE 25-1 -An Electromagnetic Wave Propagates Along the +Y Direction as Shown