Properties and Types of Light

Nature: Light behaves as both a wave and a particle (wave-particle duality).
Speed: In a vacuum, light travels at approximately 299,792 kilometers per second (km/s).
Wavelength and Frequency:
- Wavelength (λ): Distance between consecutive peaks of a wave.
- Frequency (f): Number of wave cycles passing a point per second.
- Relationship: ( c = \lambda \times f ) (where c is the speed of light).

Visible Light: The portion of the electromagnetic spectrum that can be detected by the human eye (approximately 380 to 750 nm).
Other Types:
- Infrared: Wavelengths longer than visible light.
- Ultraviolet: Wavelengths shorter than visible light.
- X-rays, gamma rays, radio waves, and microwaves.

Reflection: Light bounces off surfaces, obeying the law of reflection (( \theta_i = \theta_r )).
Refraction: Bending of light as it passes from one medium to another due to speed changes, described by Snell's law (( n_1 \sin(\theta_1) = n_2 \sin(\theta_2) )).
Diffraction: Spreading of light waves as they pass through an opening or around obstacles.
Interference: The process by which two or more light waves superimpose to form a resultant wave.

Lenses: Tools that refract light to magnify images (convex and concave lenses).
Mirrors: Reflect light to form images (plane, concave, and convex mirrors).
Prisms: Refract light to disperse it into its constituent colors (spectrum).

Additive Color Mixing: Combining primary colors (red, green, blue) to create other colors.
Subtractive Color Mixing: Combining pigments (cyan, magenta, yellow) to absorb certain wavelengths and reflect others.

Communication: Fiber optics use light to transmit data over long distances.
Imaging: Cameras and microscopes rely on light to capture and magnify images.
Medical: Endoscopy and laser surgery utilize light for diagnostics and treatment.

Photons: Light is made of particles called photons, which carry energy and have no mass.
Energy of Photons: Given by the equation ( E = hf ) (where h is Planck's constant).

Ray Theory: Treats light as straight lines (rays) traveling in space.
Wave Theory: Describes light as a wave phenomenon, including concepts like interference and diffraction.
Quantum Theory: Incorporates particle-like behavior of light, explaining phenomena such as the photoelectric effect.

Light exhibits wave-particle duality, behaving as both a wave and a particle.
In a vacuum, light travels at a speed of approximately 299,792 kilometers per second (km/s).
Wavelength (λ) is the distance between consecutive wave peaks; frequency (f) is the number of cycles passing a point per second.
The speed of light (c) is related to its wavelength and frequency: ( c = \lambda \times f ).

Visible light ranges from approximately 380 to 750 nanometers (nm) and is detectable by the human eye.
Infrared light has longer wavelengths than visible light; ultraviolet light has shorter wavelengths.
Other types of light include X-rays, gamma rays, radio waves, and microwaves.

Reflection occurs when light bounces off surfaces, following the law of reflection (( \theta_i = \theta_r )), where angles are measured from the normal.
Refraction refers to light bending as it passes between different media, governed by Snell's law (( n_1 \sin(\theta_1) = n_2 \sin(\theta_2) )).
Diffraction involves the spreading of light waves when they encounter obstacles or narrow openings.
Interference is the phenomenon where two or more light waves superimpose to form a new resultant wave.

Natural light sources include celestial bodies like the Sun and stars.
Artificial sources of light consist of light bulbs, lasers, and light-emitting diodes (LEDs).

Lenses are optical devices that refract light to magnify images; they can be convex (converging) or concave (diverging).
Mirrors reflect light to create images, categorized into plane, concave, and convex types.
Prisms refract and disperse light into its component colors, creating a spectrum.

Additive color mixing involves combining primary colors (red, green, blue) to create various colors.
Subtractive color mixing occurs by combining pigments (cyan, magenta, yellow) that absorb specific wavelengths and reflect others.

Communication technologies, such as fiber optics, utilize light to transmit data over long distances.
Imaging devices like cameras and microscopes depend on light to capture and magnify images.
Medical applications, including endoscopy and laser surgery, harness light for diagnostics and treatments.

Photons are the elementary particles of light that carry energy and are massless.
The energy of photons is represented by ( E = hf ), where h stands for Planck's constant and f is the frequency of light.

Ray theory describes light as traveling in straight lines (rays) through space.
Wave theory characterizes light as a wave phenomenon, focusing on phenomena such as interference and diffraction.
Quantum theory integrates the particle nature of light, explaining effects like the photoelectric effect.