Midterm 4: Waves and Mirrors Flashcards
Wave
a traveling disturbance that transmits energy (travels through a medium)
pulse
a single disturbance
periodic wave
regular repeating disturbance
what are the 4 types of waves
longitudinal, transverse, mechanical, and electromagnetic (EM)
longitudinal wave
the vibrating disturbance is parallel to the direction of travel of the wave
exs of longitudinal wave
sound, seismic wave (p-wave)
transverse wave
vibration is at right angles to the direction of travel of the wave
exs of transverse wave
electromagnetic (EM) wave, seismic wave (s-wave), wave on a rope/spring
mechanical wave
requires a medium to travel through
exs of mechanical wave
sound, seismic
medium
the matter through which a wave travels
electromagnetic (EM) wave
don’t require a medium to travel through
exs of electromagnetic (EM) wave
light, x-rays, radio
sound
longitudinal compression waves
visible light
transverse wave
frequency(f)
of disturbances per second
what are the units of frequency
hertz
what are the units of period
seconds
period (T)
the time it takes for one wave to pass by a given point
amplitude (A)
max. vertical displacement from rest position.
what determines the energy of a wave
amplitude
crest (peak)
the highest point above the equilibrium position
trough
the lowest point below the equilibrium position
wavelength(λ)
the distance from crest to crest or from trough to trough
what are the units for wavelength
meter (m)
what is the property of velocity
the direction of the velocity of a wave is always the same as the direction of propagation of the wave
phase
points on a wave with the same displacement from the baseline and velocity
in phase
when peaks of one wave align with the peaks of the others
out of phase
when peaks of one wave align with the troughs of the other
refraction
the change in the characteristics of a wave when it goes from one medium to another
properties that change for refraction
wavelength, velocity, direction, and amplitude
properties that stay the same for refraction
frequency and period
in the new medium, what happens if the wave travels faster
wavelength increases
in the new medium, what happens if the wave travels slower
wavelength decreases
what does the degree to which the properties of a wave change when it passes from one medium to another depend on
relative speed of the wave in the two media
index of refraction and formula
For light waves, the ratio of the speed of light in a vacuum to the speed of light in the medium
n= c/v
the index of refraction is always greater than or equal to?
1
Snell’s law (aka law of refraction) and formula
describes the relationship between the angles of incidence and refraction when a wave passes through a boundary between two different media
n1 sin(theta 1) = n2 sin (theta 2)
reflection
occurs when a wave bounces off the boundary btw. 2 media
what changes when reflection occurs?
amplitude and direction
what happens to pulse during a reflection off a fixed end
pulse is inverted when it’s reflected