Final answer:
The polarization of a light wave is determined by the direction of the oscillating electric field, which is parallel to the polarization direction. The correct answer is option 3.
Step-by-step explanation:
The polarization of a light wave is a property that defines the direction in which the wave's electric field oscillates relative to its direction of propagation. When discussing the polarization of an electromagnetic (EM) wave, such as light, it is crucial to understand that EM waves are transverse waves with electric and magnetic fields oscillating perpendicular to the direction in which the wave is moving.
Specifically, in a polarized light wave, polarization is defined by the direction parallel to the oscillating electric field, which means that option 3) 'of the oscillating electric field' is the correct answer to the question regarding the determination of a light wave's polarization.