Light and Sound Waves - Vocabulary Flashcards

Vocabulary flashcards covering key terms from the lecture notes on light and sound waves.

Dual nature of light

The concept that light behaves as both a wave (exhibiting interference and diffraction) and a particle (photons) depending on the phenomenon.

Photon

A discrete quantum of light energy; the particle aspect of light.

Interference

Pattern formed when two or more waves overlap, enhancing or cancelling each other.

Diffraction

Spreading of waves around obstacles or through openings.

Reflection

Light bouncing off a surface.

Refraction

Bending of light as it passes between media with different refractive indices.

Transmission

Passage of light through a material with little absorption.

Absorption

Light energy absorbed by a material, reducing transmitted light.

Scattering

Redirection of light in many directions by particles.

Wavelength

Distance between successive crests; related to color for visible light.

Frequency

Number of wave cycles per second; measured in hertz (Hz).

Amplitude

Maximum displacement of a wave; relates to brightness (light) or loudness (sound).

Speed of light (c)

Constant speed of light in vacuum (~299,792 km/s).

Vacuum

Space with no matter; light travels at speed c there.

Refractive index

n = c/v; measure of how much light slows in a medium.

Electromagnetic spectrum

All electromagnetic radiation from radio waves to gamma rays.

Visible light

Portion of the spectrum detectable by the human eye.

Infrared

Longer-wavelength EM radiation; associated with heat.

Ultraviolet

Shorter-wavelength EM radiation; can cause sunburn.

X-ray

High-energy EM radiation used in medical imaging; penetrates soft tissue.

Gamma ray

High-energy EM radiation from radioactive decay and cosmic processes.

Fiber optics

Transmission of information as light through thin optical fibers.

Optical fiber

Transparent, flexible strand guiding light via total internal reflection.

Laser communication

Transmission of data using modulated laser beams.

Free-Space Optical (FSO)

Laser communication through air or space without fiber.

Light modulation

Encoding information by varying light properties (intensity, phase, polarization).

GPS trilateration

Positioning method using measured distances to at least four satellites.

Atomic clock

Time standard based on atomic transitions; extremely precise.

Lidar

Light Detection and Ranging; uses reflected light to measure distance.

Sagnac effect

Phase shift caused by rotation when light travels in opposite directions around a loop.

Fiber Optic Gyroscope (FOG)

Inertial rotation sensor using the Sagnac effect in a fiber coil; no moving parts; EMI-immune.

EMI

Electromagnetic interference; unwanted disturbance in electronic systems.

Endoscopy

Medical procedure using light-guided visualization inside the body.

LASIK

Laser-assisted in-situ keratomileusis; laser reshapes the cornea to correct vision.

Ophthalmoscopy

Examination of the retina and optic nerve using light.

UV sterilization (UV-C)

Germicidal UV light (UV-C) used to kill microorganisms.

Lithotripsy

Breaking kidney stones with focused ultrasonic or shock-wave energy.

Hearing aid

Device that amplifies sound to aid hearing.

Timbre

Quality or color of a musical tone that distinguishes instruments beyond pitch and loudness.

Pitch

Perceived frequency of a sound; higher frequency = higher pitch.

Loudness

Perceived amplitude of a sound; higher amplitude = louder sound.

Compression

Region of high pressure in a sound wave; part of a cycle.

Rarefaction

Region of low pressure in a sound wave.

Echolocation

Navigation using reflected sound to detect objects; used by bats and dolphins.

Sonar

System using sound to detect objects or map surroundings underwater.