Consider an electromagnetic wave traveling in the positive y-direction. the magnetic field associated with the wave at some location at some instant points in the negative x-direction as shown in the figure below. what is the direction of the electric field at this position and at this instant?

The electric field points in the negative z-direction.

Explanation:

Electromagnetic waves are transverse, that is, the oscillation of the electric and magnetic field is perpendicular to the direction of propagation of the wave and perpendicular to each other. So, we have:

P is the poynting vector, which indicates the direction of propagation of the wave, E is the electric field and B the magnetic field. Thus, replacing the given directions:

Which is satisfied if . So, the electric field points in the negative z-direction.

pe = weightxheight = 2000x1000=2,000,000joules