3b P1 waves - speed and properties 3d LM Flashcards
what are the two types of waves?
longitudinal
transverse
what are transverse waves?
waves where the points along its length vibrate at 90 degrees to the direction of energy transfer
what are properties of transverse waves?
energy transfer is in the same direction as the wave motion
only transfers energy
move in a liquids and solids, not gas
some can move in a vacuum
what are longitudinal waves?
waves where the points along its length vibrates parallel to the direction of energy transfer
what are the properties of longitudinal waves?
energy transfer is in the same direction as the motion
only energy transfer
move in all things
can move in a vacuum
what are the key features of longitudinal waves?
points where they are close together are called compressions
where it is spaced apart its called rarefactions
what is a way to visualise the two types of waves?
transverse waves is like moving a rope up and down
longitudinal is like the vibrations of a coil
where do you draw the normal in reflection?
90degrees to the mirror or the object
where is the angle of incidence in reflection?
between the ray going in and the normal
where is the angle of reflection in reflection?
between the ray going out and the normal
where is the normal in refraction?
perpendicular to the object
where is the angle of incidence in refraction?
between the ray going in and the normal
where is the angle of reflection in refraction?
the refracted ray going into the object/water
what is n in snells law?
the refracted index
which wave changes density and pressure?
longitudinal, transverse waves don’t
what is the Doppler effect?
the apparent change in wavelength and frequency of a wave emitted by a moving source
explaining the Doppler effect?
when an object is stationary the waves emit symmetrically out from the source
when an object is moving the waves appear bunched up at the front of the moving object and spaced out at the back
what is the critical angle?
in total internal reflection when the angle becomes big enough for it to be reflected out, the incident angle becomes the critical angle
what’s total internal reflection?
it happens when light is moving from a denser medium to a less dense one when there is a large enough angle from the normal in refraction it reflects in a glass object instead of coming out at the other end
what wave is light?
transverse waves
what can light waves undergo?
reflection and refraction
what waves are sound?
longitudinal
what can sound waves undergo?
reflection and refraction
what ray is the incident ray?
the ray going in
what ray is the refracted ray?
the ray going out
why do waves change direction?
because when they move through materials with different densities they can change direction
what are the i and r angles equal too?
each other
angle of incidence = angle of reflection
what happens when a light travels from dense to more dense materials?
light bends toward the normal
what happens when a light travels from more dense to less dense materials?
light bends away from the normal
in refraction where does the light refract entering the block?
the light ray refracts toward the central line
in refraction where does the light refract when exiting the block?
the light ray refracts away from the central line
what are the two conditions needed for total internal reflection?
the angles of incidence > the critical angle
the incident material is denser than the second material
what is an oscilloscope?
a device that can be used to study a rapidly changing signal
such as
a sound wave
an alternating current
what is the pitch of a sound?
the pitch of the sound is related to the frequency of the sound waves
low wave freq is low pitch
high wave freq is high pitch
what is the loudness of a sound?
its related to the amplitude of a vibrating source of sound waves
higher amplitude = louder sound
what is the range of human hearing?
20 - 20000 Hz
