Mirrors: Reflection Fundamentals
Mirrors work on the principle of reflection. Light rays hitting the mirror's surface bounce back at identical angles. This predictable behavior is key to the formation of images, which can be either virtual or real, depending on the mirror's curvature.
Curved Mirrors: Types
Curved mirrors come in two primary types: concave and convex. Concave mirrors curve inward, resembling a cave. They can produce magnified images or focus light. Convex mirrors bulge outward, offering a wider view, hence their use in vehicle side mirrors.
Lenses: Refraction Power
Unlike mirrors, lenses rely on refraction. They bend light as it passes through, changing its direction. This bending is due to the lens's shape and the material's refractive index. Lenses can converge or diverge light, forming various image types.
Focal Point: Definition
The focal point of a lens or mirror is the spot where parallel light rays converge or appear to diverge from. For mirrors, it's along the mirror's principal axis, while for lenses, it's key to determining their optical power.
Mirrors in Telescopes
The world's most powerful telescopes use mirrors, not lenses, to capture distant cosmic light. The Hubble Space Telescope features a 2.4-meter primary mirror, offering sharp images of the universe by avoiding lens-induced chromatic aberration.
Corrective Lenses: Vision
Corrective lenses, such as glasses or contact lenses, are designed to adjust the focus of light entering the eye, compensating for imperfections in the eye's own lens. They can correct myopia, hyperopia, astigmatism, and presbyopia, enhancing visual clarity.
Invisible Glass Discovery
Surprisingly, scientists have developed a type of glass that is nearly invisible. Coated in nanolayers, it reflects almost no light and lets through 99.5% of incoming light, making it almost indistinguishable from the air around it.