If the electric field in a plane electromagnetic wave is along the y axis and its magnitude is given by E_msin (kx + t)in SI units, then the magnetic field is along the z axis and its magnitude is given by: A)(E_m/c)cos (kx + t) B)-(E_m/c)cos (kx + t) C)(E_m/c)sin (kx + t) D)-(E_m/c)sin (kx + t) E)E_mcos (kx + t)

Question

Quizplus · Accepted Answer

According to Maxwell's equations, the electric field and magnetic field in a plane electromagnetic wave are related by

B = (1/c) × E

where c is the speed of light. Therefore,

B = (1/c) × ES1U1B0sin(kx + F1F1F1S1F1F1F10t)

B = -(ES1U1B0/c) × cos(kx + F1F1F1S1F1F1F10t)

since the magnetic field is perpendicular to the electric field and pointing in the z direction. Therefore, the correct choice is D.

If the Electric Field in a Plane Electromagnetic Wave Is