Basics
What does a wave require in order to travel?
A medium
What is the unit for wave frequency? (i.e. # of cycles per time)
Hz (Hertz)
What occurs when two waves meet while traveling through the same medium?
Interference
What happens to a wave at a fixed-end boundary?
It reflects and inverts (flips)
What is the spreading of a wave around an obstacle called?
Diffraction
What is a single short disturbance that travels through a medium?
A pulse
What is the equation for wave speed? (i.e. the wave equation)
v=fλ
What is the result of two in-phase waves combining?
Constructive interference
What happens to a wave at a free-end boundary?
It reflects but does not invert
What effect causes a change in observed frequency due to the motion of the source of the wave?
Doppler Effect
True or False. Mass is transferred (displaced) with a wave.
(Mass moves from the source of the wave to its destination)
False
What is the distance between two crests?
1 Wavelength (1 λ)
What is the name of the point where destructive interference occurs?
Node
Which wave property remains constant across a boundary into a new medium?
Frequency
A wave source moving toward you appears to have a __________ frequency.
Higher
What term describes a regularly repeating disturbance in a medium?
A periodic wave
How are period (T) and frequency (f) related?
T=1/f
What term describes the phenomenon when waves reinforce (increase in amplitude) each other due to matching frequencies?
Resonance
What term describes the change in direction of a wave as it passes into a new medium?
Light going from air to water
Refraction
What forms when two identical waves travel in opposite directions in the same medium?
Standing wave
Give one example of a mechanical wave.
Sound, Water waves, Seismic waves, Rope Waves
A wave has a frequency of 5 Hz and a wavelength of 2 m. What is its speed?
v=fλ=(2m)(5Hz)=10m/s
Why did the Tacoma Narrows Bridge collapse?
Resonance from wind matched the natural frequency of the bridge
What property changes during diffraction?
Direction, not wavelength or frequency
What is the distance between two nodes in a standing wave?
1/2 λ
A wave traveling through a rope hits a rigid wall. Describe what happens to the wave in terms of reflection, inversion, frequency, wavelength, amplitude, and speed. Assume no energy is lost.
The wave reflects, inverts (fixed end), and returns with the same speed, frequency, and amplitude.