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

An electromagnetic wave consists of mutually perpendicular electric and magnetic fields that oscillate perpendicular to the direction of propagation. In this case, the electric field is along the +z direction. According to the right-hand thumb rule, if we point our right thumb along the direction of propagation (+y), the curl of our fingers indicates the direction of the magnetic field. Since the electric field is along the +z direction, the magnetic field must be along the +x direction, perpendicular to both the electric field and the direction of propagation. Therefore, option D) +x is the correct choice.

An Electromagnetic Wave Propagates Along the +Y Direction as Shown