Intro to Waves and Sound Flashcards
What is periodic motion?
Motion that repeats in a regular cycle (e.g., a pendulum, a mass on a spring).
What is amplitude?
The maximum displacement from equilibrium in a wave.
What is wavelength (
𝜆
λ)?
The distance between two successive crests or troughs in a wave.
What is frequency (
𝑓
f)?
The number of cycles per second, measured in Hertz (Hz).
How do transverse waves move?
Particles move perpendicular to wave motion (e.g., water waves, light waves).
How do longitudinal waves move?
Particles move parallel to wave motion (e.g., sound waves).
What are compressions and rarefactions in longitudinal waves?
Compressions are high-pressure regions; rarefactions are low-pressure regions.
What is the key difference between mechanical and electromagnetic waves?
Mechanical waves require a medium (e.g., sound), while electromagnetic waves do not (e.g., light).
Can sound travel through space?
No, sound needs a medium like air, water, or solids.
Can electromagnetic waves travel through a vacuum?
Yes, they do not need a medium.
What is the universal wave equation?
v=fλ (Wave speed = Frequency × Wavelength).
If a wave has a frequency of 200 Hz and a wavelength of 1.5 m, what is its speed?
v=200×1.5=300 m/s.
What factors affect the speed of sound?
Medium (fastest in solids, slowest in gases), Temperature (higher temp = faster speed), Humidity (higher humidity = faster speed).
What is the formula for the speed of sound in air?
v=331.4+0.6T, where
𝑇
T is in °C.
What is Mach number?
The ratio of an object’s speed to the local speed of air
.
How is loudness related to amplitude?
Higher amplitude = louder sound; lower amplitude = softer sound.
What happens to pitch when a sound source moves toward you?
Pitch increases (higher frequency).
What happens to pitch when a sound source moves away from you?
Pitch decreases (lower frequency).
How is pitch related to frequency?
Higher frequency = higher pitch; lower frequency = lower pitch.
What is a Wave?
Disturbance that transports energy from one place to another
The speed of the wave depends on (___), and the frequency depends on (____)
medium, source
