Properties of Light and Refraction

Nature of Light:
- Electromagnetic radiation visible to the human eye.
- Travels in waves and behaves both as a wave and a particle (photon).
Speed of Light:
- In a vacuum: approximately 299,792 km/s (about 186,282 miles per second).
- Slower in media like air, water, and glass.
Wavelength and Frequency:
- Wavelength: Distance between consecutive peaks of a wave.
- Frequency: Number of waves that pass a point in one second.
- Inversely related: Higher frequency means shorter wavelength and vice versa.
Color:
- Visible light spectrum: Ranges from approximately 380 nm (violet) to 750 nm (red).
- Different colors correspond to different wavelengths.

Definition: Bending of light as it travels from one medium to another, due to a change in speed.
Snell's Law:
- Describes the relationship between angles and indices of refraction:
  - n1 * sin(θ1) = n2 * sin(θ2)
  - n = index of refraction; θ = angle of incidence/refraction.
Applications:
- Lenses: Focus or disperse light for glasses, cameras, and microscopes.
- Prisms: Separate white light into its component colors.

Definition: Bouncing back of light when it hits a surface that it cannot pass through.
Law of Reflection:
- Angle of incidence equals angle of reflection.
- Both angles measured from the normal (perpendicular to the surface).
Types of Reflection:
- Specular Reflection: Smooth surfaces (e.g., mirrors) reflect light in a single direction.
- Diffuse Reflection: Rough surfaces scatter light in multiple directions.
Applications:
- Mirrors in everyday use.
- Reflective surfaces for safety and visibility (e.g., road signs).

Light is a form of electromagnetic radiation visible to the human eye.
Exhibits dual nature as both a wave and a particle (photon).
Speed of light in a vacuum is approximately 299,792 km/s (186,282 miles per second).
Light travels slower in substances such as air, water, and glass.
Wavelength refers to the distance between consecutive peaks of a wave; frequency is the number of waves passing a point per second.
Wavelength and frequency are inversely related; a higher frequency results in a shorter wavelength and vice versa.
The visible light spectrum ranges from about 380 nm (violet) to 750 nm (red), with different colors corresponding to specific wavelengths.

Refraction is the bending of light as it transitions between different media due to changes in its speed.
Snell's Law quantifies the relationship between the angles of incidence and refraction, expressed as n1 * sin(θ1) = n2 * sin(θ2), where n is the index of refraction and θ is the angle.
Lenses utilize refraction to focus or disperse light, important for glasses, cameras, and microscopes.
Prisms leverage refraction to separate white light into its constituent colors.

Reflection occurs when light bounces back from a surface that it cannot penetrate.
The Law of Reflection states that the angle of incidence is equal to the angle of reflection, both measured from the normal line (perpendicular to the surface).
Specular reflection occurs on smooth surfaces, such as mirrors, leading to uniform light reflection in a single direction.
Diffuse reflection happens on rough surfaces, scattering light in various directions.
Common applications include mirrors for personal grooming and reflective surfaces for enhanced safety and visibility, such as road signs.

Light functions as both an electromagnetic wave and a particle known as a photon.
The speed of light in a vacuum is approximately 299,792 kilometers per second.
Visible light wavelengths range from about 400 nanometers (violet) to 700 nanometers (red).

Reflection refers to light bouncing off surfaces, adhering to the law of reflection where the angle of incidence equals the angle of reflection.
Refraction occurs when light bends as it transitions between different media, a phenomenon explained by Snell's Law.
Diffraction is the spreading of light waves as they encounter obstacles or narrow openings.
Interference involves the superposition of light waves, producing patterns of constructive and destructive interference.

Natural light sources include the sun and stars.
Artificial light is generated by human-made devices, such as light bulbs and LEDs.
Monochromatic light consists of a single wavelength, exemplified by laser light.
Polychromatic light contains multiple wavelengths, as seen in sunlight.

Illumination is essential for lighting homes, streets, and workplaces.
Communication via fiber optics utilizes light signals to transmit data efficiently.
Photography relies on light-sensitive materials to capture images.
Medical applications include the use of lasers in surgical procedures and light therapies for various treatments.

The process of vision involves light entering the eye, focusing on the retina, and converting it into electrical signals sent to the brain.
Color vision is determined by wavelengths of light absorbed by photoreceptor cells (cones) located in the retina.
Visual illusions arise from the interaction of light with objects and how our brains perceive these interactions.

Quantum theory explains the particle nature of light, where photons act as quantized packets of energy.
Light exhibits dual nature, demonstrating both wave-like and particle-like characteristics (wave-particle duality).
The electromagnetic spectrum encompasses a range of electromagnetic radiation types, including gamma rays, X-rays, ultraviolet, infrared, microwaves, and radio waves.

Luminance quantifies the visible light emitted from a surface.
Illuminance measures the luminous flux spread across a specific area.
Color temperature characterizes the hue of a light source and is measured in Kelvin (K), with lower values indicating warm colors and higher values indicating cool colors.