An electric dipole with its center located at the origin of a cartesian coordinate system oscillates along the x axis, creating an electromagnetic wave.
part a: at a position on the z axis far from the origin, what is the polarization of the wave?
part b: at a position on the axis far from the origin, what is the polarization of the wave?

The wave propagates on the z axis and the polarization is linear on the x axis

Explanation:

Part A

When the two dipole charges oscillate they form a fluctuating wave that propagates in the perpendicular direction, so if the oscillation of the magnetic field is on the axis and the propagation of the wave occurs on the z-axis.

The polarization of the electric wave is equal to the direction of the electric field, therefore as the field oscillates on the x-axis the polarization is also on the x-axis and is linearly polarized.

Part B

The wave propagates on the z axis and the polarization is linear on the x axis

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.