Waves Flashcards
What is amplitude
half the crest to trough distance
what is wavelength
the distance between any part of the wave and the next part where the wave repeats itself
what is frequency
the number of waves produced in 1 second
what is period
the time it takes to make 1 wave
what is a wavefront
a line joining together similar points on a wave
what are transverse waves
Waves that vibrate or oscillate perpendicular to the direction of energy transfer
what are longitudinal waves
oscillations occur parallel to direction of energy
what is frequency measured in
Hertz (Hz)
what is the doppler effect
The apparent change in observed wavelength and frequency of a wave emitted by a moving source relative to an observer
what is the electromagnetic spectrum (in order shortest - longest)
gamma rays
x - rays
ultraviolet
visibe
infared
microwaves
radio
what is the electromagnetic spectrum for light (in order shortest - longest)
indigo
blue
green
yellow
orange
red
what kind of waves are light waves
transverse waves
what can be done light waves
they can be reflected and refracted
what is the law of reflection
angle of incidence = angle of reflection
explain the image in a mirror
images are formed when the light ray bouncing off of an object onto a mirror are diverging so they light from the object appears to be in a different place
what bends twards the normal
light going from air to glass
what bends away from normal
light going from glass to air
what is the cirtical angle
the angle of incidence for which the angle of refraction is 90 degrees
what is total internal relfection
if the angle is bigger than the cirtical angle
what are examples of total internal reflection
periscope
endoscope
fiber optics
what kind of wave is a sound wave
longitudinal wave
how can a sound wave be refracted
if it travels from one density (temperature) to another
what does high frequency mean
a sound with a high pitch
what is the range of human hearing
20Hz - 20000 Hz
what does it mean if the wave is further apart
quite and low pitched
what does it mean if the waves are close together
loud and high pitched
how can you investigate the speed of sound
using a clapper board one person stands away and they start the stopwatch when they see the clapper board touch and then stop when they hear the sound
how are microwaves a hazard
they can cause internal heating of body tissues
how is ultraviolet light a hazard
increases the rish of skin cancer and blindness
what are radio waves used for
radio and television communications
what are microwaves used for
satellite transmissions and cooking
what is infared radiation used for
heaters and night vision equipment
what is visible light used for
fibre optics and photography
what is ultraviolet used for
fluorescent lamps
what are x - rays used for
medical imaging and security
what is gamma radiation used for
sterillising food and medical equipment
what is different of how waves transfer energy
they only transfer energy and not particles
ways where we can observe the doppler effect
The frequency of the sound waves emitted by ambulance or police sirens goes from a high pitch (high frequency) to a low pitch (low frequency) as the vehicle whizzes past
Galaxies in outer space emit light waves which appear redder (longer wavelength) to an observer on Earth because the stars are moving away from us
draw a ray diagram for the reflection of light
what is refraction
when a wave slows down or speeds up at a boundary between two materials
draw a ray diagram for a refracted light ray
what is a part of the electromagnetic specturm that includes everything
ight is part of a continuous electromagnetic spectrum that includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations and that all these waves travel at the same speed in free space
what are the dangers of infared radiation
skin burns
what are the dangers of gamma rays
cancers and mutation
how to protect yourself againsts dnagerous electromagnetic waves
ultraviolet - sunscreen, sunglasses
gamma and x rays - use low levels and avoid uneccesary contact
infared - wear protective clothing
what is the investigation for the refraction of light
investigating useing rectangular blocks, semi circular blocks and triangular prisms
results from investigating the refraction of light
when light travels from one medium to another medium, it changes its path this is because the speed of light will change.
what is the experiment for the refractive index of glass
passing rays of light through a glass box to find the refractive index of glass
set up for investigaing the refractive index of glass
what are optical fibres
they are made of plastic or glass and consist of a central core surrounded by coating with a lower refractive index
how do optic fibres work
the core of the fibre is so narrow that light signals passing through it always hit the core cating boundary so the light is always internally reflecting
what is an oscilloscope
a device which can display the microphone signal as a trace on a screen
how does the ocilloscope display sound waves
the appreance of the wave on the screen tells you weather it is loud or quite and high or low pitched.
you can take detailed measurements to calculate the frequency by adjusting the settings of the display
draw the 4 common traces from an oscilloscope
how does pitch and sound relate to frequency
A high pitch sound corresponds to a high frequency sound wave
a low pitch sound corresponds to a low frequency sound wave
how does loudness of sound relate to the amplitude of vibration
The greater the amplitude the louder the sound. Bigger vibrations of a sting mean more energy is being put in so more energy out as sound waves.
