Axis of a polarizing filter

Definition

The axis of a polarizing filter is the direction along which the filter allows light waves with specific orientations to pass through. It determines the plane of polarization for transmitted light.

5 Must Know Facts For Your Next Test

1. The axis of a polarizing filter is usually marked on the frame or edge of the filter.
2. A polarizing filter only allows light waves vibrating parallel to its axis to pass through.
3. When two polarizing filters are placed perpendicular to each other, they block all light from passing through.
4. The intensity of transmitted light through a polarizing filter can be described using Malus's Law: $I = I_0 \cos^2(\theta)$, where $\theta$ is the angle between the light’s initial polarization direction and the filter's axis.
5. Polarizing filters are commonly used in sunglasses and cameras to reduce glare.

Review Questions

• What happens to light when it passes through a polarizing filter aligned with its axis?
• How does placing two polarizing filters at 90 degrees relative to each other affect light transmission?
• What law describes the intensity of transmitted light through a polarizing filter?

Related terms

Polarization:

The orientation of oscillations in a transverse wave, especially in electromagnetic waves like light.

Malus's Law:

A mathematical equation that describes how the intensity of polarized light changes as it passes through a polarizer at an angle.

Transmitted Light: Light that has passed through a medium or surface, such as a polarizing filter.