Understanding Light Propagation, Reflection, and Refraction

Propagation of Light

Light propagates in all directions and undergoes processes such as reflection, refraction, and attenuation. Light interacts with all surfaces and can be categorized as follows:

Types of Reflection

• Specular Reflection: Occurs on polished surfaces. Mirror images are visible because all light rays are deflected equally.
• Diffuse Reflection: Occurs on most surfaces. Mirror images cannot be seen because surface irregularities cause scattered reflections.

Shadows and Penumbras

A direct effect of the rectilinear propagation of light is the formation of shadows. In these areas, a fuzzy edge called the penumbra is visible, which forms when the light source has a considerable size.

How Mirrors Work

Mirrors are constructed of flat glass coated with aluminum on one side. The aluminum reflects most of the light it receives, producing a specular reflection. If a mirror is not completely level, the image will appear distorted.

Telescopes and Curved Mirrors

Large telescopes use curved mirrors to enlarge observed objects. The curved surface has a greater capacity to capture light and focus it onto a single point.

Refraction of Light

Light is deflected when entering a transparent medium because its propagation speed changes.

Decomposition of White Light

The deviation experienced by refracted light increases with its frequency. This effect is exploited in glass prisms to reveal the visible light spectrum.

Absorption and the Origin of Color

Each material absorbs photons of certain frequencies and reflects the rest:

• White materials: Reflect nearly all light.
• Black materials: Absorb almost the totality of light, which is why black objects heat up more when illuminated.

The color we perceive in an object depends on the spectrum of light received, the frequencies absorbed, and how our brain processes visual information. Color blindness is a hereditary disorder that alters this perception.