Question

A plane electromagnetic wave traveling in a vacuum has a magnetic field of the form: B = Bo sin(kz+ wt)j^ In which direction is the EM wave traveling?

1. x
2. -x
3. y
4. -y
5. z
6.-z

Answer 1

The plane electromagnetic wave, with its magnetic field oscillating in the y-direction, is traveling in the direction of the z-axis.

So, the correct answer is option 5. z

Step-by-step explanation:

Based on the given information about the electromagnetic wave, where the magnetic field B is given by B = Bo sin(kz + wt)j^, we can determine the direction in which the EM wave is traveling. According to Maxwell's equations and the properties of electromagnetic waves, the electric field (E), magnetic field (B), and the direction of wave propagation are all mutually perpendicular to each other.

Since B is oscillating in the j^ direction (which corresponds to the y-axis), and the wave equation involves the variable z, we can conclude that the E field must be oscillating in the x-axis direction. Therefore, the wave must be propagating in the direction of the z-axis, as the sinusoidal variation is with respect to z. The correct option is 5. z.