Waves Flashcards
a wave is a
transfer of energy
examples of waves
vibrations, sound, water, seismic
2 general catagories of waves
electrogmagnetic and mechanical
What are electromagnetic waves & exampls
- waves that are produced by the back and forth motion of tiny particles - they travel through space requiring no material (medium). They can transmit energy through a vacum - ex. light, radio, x-rays, infrared
what are mechanical waves & ex
- waves that deal w/ matter and mass - they travel through a medium ex. sound, water waves, jump rope waves
T/F they both require a medium in order to exist
T
What are 3 types of mechanical waves
- transvere waves, longitudinal, surface
transverse waves
- a wave in which particles of the medium move in a direction perpendicular to the direction that the wave moves
longitudinal waves
waves in which particles of the medium move in a direction parallel to the direction that the wave moves (sound wave) - only longitudinal waves can travel through liquids
surface waves
a wave in which particles of the medium undergo a circular motion
medium
the matter that the wave moves through
crest
top part of the wave
trough
bottom part of the wave
amplitude (A)
magnitude of a wave
Wavelength
distance for one complete wave (m)
period (T)
time for one complete wave to pass a point
Frequency (f)
number of crests that pass a particular point per unit of time - measured in Hz
wave equation
speed = frequency X wavelength
As a wave travels through a medium what will often happen?
it will often reach the end of the medium and encounter an obstacle or perhaps another medium through whitch it could travel
when one medium ends and another begins; the interface of the two mediums are called
a boundry
the behaviour of a wave at that boundry is described as
boundry behaviour
what does not change as waves move from one medium into another
frequency
what are the 2 most common behaviours of the wave
reflection or refraction
when does reflection occur
when a wave hits another boundry and reflects back
when does refraction occour and what is it
refraction is the bending of a wave it occurs when the wave hits an object at an angle or enters a new medium it results from the change in a wave’s speed
SPEED OF A WAVE - depends on - speed of water waves depend on - speed of rope waves depend on - speed of sound in air depends on
- properties of the medium - depth of water - force extered on the rope - temp (lower=denser=slower)
T/F waves can be at the same place at the same time
T
What is the superposition principle
when one or more waves occupy the same space at the same time, the displacements add at every point
what is the result of the superposition of two or more waves called
interferance
within an interferance pattern wave effects may be
increased, decreased, neutralized