Which of the following optical properties of light enables sunglasses to reduce glare from sunlight reflected off surfaces such a…

Question

Which of the following optical properties of light enables sunglasses to reduce glare from sunlight reflected off surfaces such as water or roads?

1. A. Refraction
2. B. Diffraction
3. C. Interference
4. D. Polarization (Correct answer)

Correct Answer

Option D — Polarization

Detailed Solution & Explanation

The correct answer is Polarization.

Key Points

• Polarization is the property that lets sunglasses cut glare. Light reflected from a horizontal surface such as water or a road becomes largely horizontally polarized, and a polarizing filter oriented vertically blocks that component while admitting the rest.
• The other properties describe different phenomena: refraction is bending on entering a new medium, diffraction is bending around obstacles, and interference is the superposition of waves.

Additional Information

• Polarization is possible only for transverse waves, so the fact that light can be polarized is direct evidence that light is transverse. Sound cannot be polarized, being longitudinal — a favourite examination contrast.
• The angle at which reflected light is completely polarized is Brewster's angle, given by $\tan\theta_B = \dfrac{n_2}{n_1}$.
• Everyday applications extend well beyond sunglasses: LCD screens, photographic filters that darken skies and cut reflections, and 3D cinema glasses, which feed a differently polarized image to each eye.
• Ordinary sunglasses merely reduce overall intensity; polarized lenses selectively remove the glare component, which is why they improve contrast rather than just dimming the view.