Waves Flashcards
waves transfer
energy from place to place with transferring matter
waves can be
reflected, refracted and defracted
wavelength definition
the distance from a point on the wave to the equivalent point on the adjacent wave
peak definition
top of the wave
amplitude definition
the maximum displacement of a point on the wave from its undisturbed position
trough definition
bottom of the wave
frequency definition
the number of waves passing a fixed point every second
time period definition
the time taken for each wave to pass a fixed point
wave speed definition
the distance travelled by each wave every second through a medium
wave speed equation
frequency x wavelength
speed equation
distance / time taken
reflection definition
the change of direction of a light ray when it passes across a boundary between two transparent substances
refraction definition
the change of direction of a light ray when it passes across a boundary between two transparent substances
wavelets move
forward together to recreate the wavefront that created them
what is the speed of light
3 x 10 to the power of 3 m/s
angle of incidence and angle of reflection
angle of incidence = angle of reflection
angle of incidence and angle of refraction across air and glass
opposite angles
space is
a vacuum meaning no sound
auditory nerve
sends electrical signals to the brain
ossicles
three small bones (hammer, anvil and stirrup)
eat drum
a sheet of muscle and skin
ear canal
eat passage with wax and hair
pinna
the ear flap
semi-circular canals
helps to balance
cochlea
coverts vibrations into electrical signals
ultrasound
sound that has a frequency above the range of human hearing
infrasound
sound with a frequency below the range of human hearing
range of human hearing
20hz - 20khz
waves are sent
toward the foetus
technology works out
the distance between where the wave was set off from to where it hit the foetus
3 things that can happen when a wave hits a boundary
reflect
transmit (refract if at an angle and speed change)
absorbed
transducer
create an ultrasound wave
ultrasound will travel
through the body and will partially reflect at a boundary between tissues
some of the wave will
transmit into the next layer of tissue
transducer detects
reflections as a pulse
distance equation
speed x time
p waves
longitudinal wave
‘push-pull’ effect on building causing ‘up-down’ moment
travel through solid + liquid
primary ‘first’ wave
s waves
transverse waves
‘side to side’ effect on building causing ‘left to right’ movement
only travel through solid
seismic ‘second’ wave
dark colour are the
best emitters of radiation
matte surface is the
best emitter if radiation
colour spectrum
red
orange
yellow
green
blue
indigo
violet
speculate reflection
smooth surfaces
difficult reflection
rough surfaces
waves for detection and exploration
high frequency sound waves can be used to detect objects in deep water and measure water depth
electromagnetic waves
transverse waves with a wide range of properties and uses
infra-red radiation
a part of electromagnetic spectrum
uses of electromagnetic waves
redos waves - television and radio
microwave s- satellite communications and cooking food
infrared - electrical heaters, cooking food and infrared cameras
visible light - fibre optic communications
lenses
concave and convex lenses
visible light
the visible region of the electromagnetic spectrum
black body radiation
name given to the thermal radiation emitted by all bodies (objects)
ripple tank required practical
measure and calculate frequency, wavelength and the speed of waves on the surface of the water
what is a longitudinal wave?
is parallel to the direction the wave travels
p-waves
sound waves, ultrasound waves
what is a transverse wave?
is perpendicular to the direction the wave travels
s-waves
radio waves, light waves
period equation
period = 1/frequency
what is a method used to measure the speed of sound waves in air
clap-echo method
This method involves measuring the time taken for you to hear an echo from a sharp clap. You stand a long distance from a wall, clap, and listen for the echo. The distance travelled is twice the distance from you to the wall (because the sound has to travel to the wall and back)
what is a method used to measure the speed of ripples on a water surface
ripple tank method
A ripple tank is a transparent shallow tray of water with a light shining down through it onto a white card below. The light allows you to see the motion of the ripples created on the water’s surface more easily. Ripples can be made by hand but to generate regular ripples it is better to use a motor
how are sound waves formed
Sound waves are created by object vibrations and produce pressure waves, for example, a ringing cellphone. The pressure wave disturbs the particles in the surrounding medium, and those particles disturb others next to them, and so on
what are ultrasound waves and how are they used to determine how far away a boundary is?
sound waves
they pass through softer tissue but reflect denser tissue
what are seismic waves and how can they tell us about the earths structure?
seismic waves can only travel through solids so they can tell us that the earth has liquid layers
what is echo sounding?
high frequency sound waves used to detect objects in deep water or measure water depth
what are some common properties of electromagnetic waves?
all transverse waves
can travel through a vacuum
travel at exactly the same speed in vacuum (speed of light)
transfer energy from one place to another
can be reflected and refracted
what are all of the parts of the electromagnetic spectrum?
radio waves
micro waves
infra red
visible light
ultraviolet
x-rays
gamma rays
how do different substances absorb, transmit, refract or reflect electromagnetic waves?
how are radio waves sent and received?
transmitter radiates electromagnetic waves outwards via an antenna and a receiver picks up the waves and translates them into sounds that can be heard
how are gamma waves produced?
by charges in the nucleus of an atom
what are the dangers of ultraviolet, x-rays and gamma?
ultraviolet = sunburn, premature aging, skin cancer
x-ray = cancer many years or decades later
gamma = destroy living cells, produce gene mutations and cause cancer
what are the uses of each part of the electromagnetic spectrum?
radio = radio and television
microwaves = satellite communications and cooking food
infrared = electrical heaters, cooking food and infrared cameras
visible light = fibre optic communications
ultraviolet =energy efficient lamps, sun tanning
x-rays = medical imaging and treatment
gamma = medical imaging and treatments
how do convex lens produce an image?
causes rays of light to converge
how do concave lens produce an image?
causes rays of light to diverge
how do you calculate magnification and why does it have no units?
using a scaler bar
it has no units as it is a ratio of low lengths
what is the difference between specular and diffuse reflection?
specular = smooth surfaces like mirrors causes light rays to reflect at the same angle they hit the surface
diffuse = rougher surfaces scatter light rays in different directions
how do colour filters work?
when white light passes through a coloured filter, all colours are absorbed except for the colour of the filter
how does colour link to frequency and wavelength?
each colour has a different wavelength and frequency
why do objects appear to be a certain colour?
they absorb some colours and reflect or transmit other colours
what is a black body?
the spectrum of light emitted by any heated object e.g. heating of a toaster, filament of a light bulb
bodies emitting radiation
all bodies emit radiation and the intensity and wavelength distribution of any emission depends on the temperature of the body
the body temp and radiation
the body at a constant temp absorbs radiation at the same rate as it is emitting radiation. the temperature of a body increases when the body absorbs radiation faster than it emits
what factors affect the temperature of the earth?
as the earth internal energy increases the surface gets hotter
