waves for y11 mocks Flashcards
(38 cards)
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)