waves for y11 mocks Flashcards
what do waves do
transfer energy from one place to another but no matter
why is our brain able to build up images or tunes from light and sound it recieves
as we can interpret sometimes the energy as meaningful information
what is period
time it takes for 1 complete oscillations
what is frequency
no of complete oscillations per secons
tranverse
oscillations are perpendicular to direction of energy transfer
what are examples of transverse waves
em waves
water waves
strings on guitar
longitudinal waves are and have
sound waves and seismic P waves
they have compressions and rarefactions
what may happen when waves hit a boundary
absorbed
transmitted
reflected
what is specular reflection
when normals are all in the same direction as the surface is flat eg a mirror so we can see ourselves from the clear image that is produced
what is diffuse reflection
when the surface of a material is uneven so normals are all in many different directions so you cant normally see yourself
when does refraction happen
when a ray enters a medium at an angle
when a material enters a less dense medium
the ray refracts away from the normal
what happens if you pass white light through a triangular prism
all colours will bend to different degrees creating a rainbow from all the spread out colours
When a wave travels into a more dense medium, the wave speed decreases what happens to the frequency
stays the same
em waves speed in a vacuum
3x10 8 m/s
how can we generate radio waves
use a transmiter connected to an oscilloscope to see frequency of wave we produce which is the same as the alternating current
generate radio wave
use reciever to absorb energy and generate alternating current which is displayed on another oscilloscope
convex/converging
direct rays of light to principal focus
concave
disperse the light
the shorter the focal length
the stronger the lens/more curved
image is always virtual
when a concave lens is used
on a convex lens when do you draw dotted lines
when object is within focal length as the real rays will never meet
what affects the colour appears
wavelengths of light hitting it
the properties of the object
what do opaque objects do to light
they either absorb or reflect all wavelengths of light(or maybe range eg red and green making yellow)
for transparent objects what happens to light
most light would be transmitted with only small fraction absorbed or reflected(eg glass in windows)
for translucent objects what happens to light
they only transmit some light with the colour being which wavelengths transmitted most
how do colour filters work
they only allow certain wavelengths to pass through and absorbing rest
an object cooler or warmer than its surroundings
cooler will warm slowly
warmer will cool slowly
as temperature on an intensity increases
the intensity of every emitted wavelength also increases(with short increasing more than longer wavelengths)
what is intensity
how much energy radiation transfers to a given area in a certain amount of time
why is the earth hotter in the day
more energy is absorbed than emitted but at night this is opposite
what happens to the freq in sound waves
stays the same
what is the range of human hearing
20-20000hz
what is ultrasound
frequencies above 20000hz
what are some ways we use ultra sound
pre natal scanning where waves reflected are detected or checking quality of products in industry
there is also echo sounding which we use s=dt
what are seismic waves types
P waves and S waves
why do bats produce echo location
to communicate and for echolocation
describe P waves and S waves
P waves-longitudinal and travel through solids and liquids-much faster
S waves are transverse -only go through solids
what would the journey of P waves be
it would constantly be refracted and curve as it goes through different mediums (liquid outer core/mantle)
