Physics Flashcards
(22 cards)
What is a wave?
A wave is a repeated disturbance that transfers energy without transferring matter.
What are the two types of waves?
- Transverse: particles move perpendicular to the wave.* Longitudinal: particles move parallel to the wave.
What happens during reflection?
When a wave bounces off a surface.
What is the relationship between the angle of incidence and the angle of reflection?
Angle of incidence = angle of reflection.
What types of waves undergo reflection?
- Light* Sound* Water waves.
What is refraction?
When a wave changes direction and speed as it enters a new medium.
What causes refraction?
A change in wave speed due to different densities of materials.
Give an example of refraction.
A straw looks bent in water.
What happens to light when it slows down in a denser medium?
Light bends toward the normal.
What is diffraction?
When a wave spreads out as it passes through a gap or around an obstacle.
What increases the amount of diffraction?
- The gap is small* The wave’s wavelength is long.
Provide an example of diffraction.
Hearing sound around a corner.
What are electromagnetic (EM) waves?
Transverse waves that do not need a medium — they travel in a vacuum.
What is the speed of EM waves?
Travel at the speed of light (~300,000 km/s).
List the EM Spectrum from low to high frequency.
- Radio waves* Microwaves* Infrared* Visible light* Ultraviolet* X-rays* Gamma rays.
What are some uses of EM waves?
- Communication* Medicine* Remote controls.
What is ultrasound?
Sound waves with frequencies above 20,000 Hz (beyond human hearing).
What are some applications of ultrasound?
- Medical imaging (e.g., baby scans)* Industrial testing (finding cracks)* Sonar and distance measurements.
How do ultrasound waves work in medical imaging?
Ultrasound waves reflect off boundaries inside the body or object.
What is the speed of sound in air?
~343 m/s.
What happens to light when it changes speed?
It refracts, causing bending.
When is diffraction most noticeable?
With long wavelengths (like sound).
