WAVES AND ENERGY Flashcards
What is Energy?
The ability to do work or cause change; measured in joules (J).
Forms of Energy
Kinetic, Potential, Thermal, Chemical, Electrical, Nuclear, Radiant, Mechanical.
Kinetic Energy
Energy of motion; depends on mass and velocity (KE = 1/2 mv^2).
Potential Energy
Stored energy due to position or state (e.g., gravitational, elastic, chemical).
Thermal Energy
Energy related to heat and temperature; caused by particle movement.
Chemical Energy
Stored in chemical bonds; released during chemical reactions (e.g., food, batteries).
Electrical Energy
Energy from moving electrons (e.g., lightning, circuits).
Nuclear Energy
Energy stored in atomic nuclei; released in fission and fusion.
Radiant Energy
Energy carried by electromagnetic waves (e.g., light, X-rays, radio waves).
Mechanical Energy
Sum of kinetic and potential energy in a system (e.g., a moving car).
Law of Conservation of Energy
Energy cannot be created or destroyed, only transformed from one form to another.
Examples of Energy Transformation
Chemical to mechanical (food to movement), electrical to thermal (heater), kinetic to potential (swinging pendulum).
Renewable Energy Sources
Solar, wind, hydro, geothermal, biomass; naturally replenished.
Non-Renewable Energy Sources
Fossil fuels (coal, oil, natural gas), nuclear; limited supply.
Work and Energy Relationship
Work is done when energy is transferred to an object (Work = Force × Distance).
Power
The rate of energy transfer; measured in watts (W).
What is a Wave?
A disturbance that transfers energy through matter or space.
Types of Waves
Mechanical Waves and Electromagnetic Waves.
Mechanical Waves
Require a medium (solid, liquid, or gas) to travel through (e.g., sound, water waves).
Electromagnetic Waves
Do not require a medium; can travel through space (e.g., light, X-rays, radio waves).
Transverse Waves
Particles move perpendicular to wave direction (e.g., light, water waves).
Longitudinal Waves
Particles move parallel to wave direction (e.g., sound waves).
Parts of a Wave
Crest (highest point), Trough (lowest point), Wavelength (distance between two crests/troughs), Amplitude (height of wave).
Wave Frequency
Number of wave cycles per second; measured in Hertz (Hz).
Wave Speed Formula
Wave Speed = Frequency × Wavelength.
Sound Waves
Mechanical longitudinal waves that travel through air, water, or solids.
Light Waves
Electromagnetic transverse waves that do not need a medium to travel.
Reflection
Bouncing back of a wave when it hits a surface (e.g., echo, mirror reflection).
Refraction
Bending of a wave as it enters a new medium (e.g., pencil in water appears bent).
Diffraction
Waves spreading out after passing through a gap or around obstacles.
Interference
When two waves meet and combine (constructive or destructive).
Doppler Effect
Change in frequency due to motion of the source or observer (e.g., ambulance siren changes pitch).
Electromagnetic Spectrum
The range of all types of electromagnetic radiation, arranged by wavelength and frequency.
Order of EM Spectrum (Lowest to Highest Frequency)
Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-Rays, Gamma Rays.
Visible Light Spectrum
The part of the EM spectrum that can be seen by the human eye.
Colors of Visible Light (Lowest to Highest Frequency)
Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).
Red Light
Longest wavelength, lowest frequency, least energy.
Violet Light
Shortest wavelength, highest frequency, most energy.
Infrared Waves
Lower frequency than red light; used in heat sensors, night vision, and remote controls.
Ultraviolet (UV) Waves
Higher frequency than violet light; can cause sunburn, used for sterilization.
X-Rays
Even higher energy; used in medical imaging.
Gamma Rays
Highest energy, shortest wavelength; used in cancer treatment and nuclear reactions.
Radio Waves
Longest wavelength, lowest frequency; used in communication (radio, TV, cell phones).
Microwaves
Shorter than radio waves; used in cooking, radar, and satellite communication.
Infrared Waves
Used in remote controls, night vision, and detecting heat signatures.
Visible Light
The only part of the EM spectrum visible to humans; colors range from red to violet.
Ultraviolet (UV) Waves
Higher energy than visible light; used in sterilization and can cause sunburn.
X-Rays
Used in medical imaging to see inside the human body.
Gamma Rays
Highest energy, shortest wavelength; used in cancer treatment and emitted by nuclear reactions.
