physics paper 2 Flashcards
(30 cards)
amplitude
distance from the middle to the top/bottom of a wave
symbol - A, unit depends on the wave
wavelength
distance from one point on a wave to the same point on the next wave
symbol - lambda, units - metres (m)
frequency
number of waves per second
symbol - F, units - hertz (Hz)
time period
time for one wave to pass a given point/ time taken for a wave to complete one oscillation
symbol - T, units - seconds (s)
time trace graphs
shows how displacement changes with time for a certain position
time period is measured how wavelength is measured
snapshot graphs
shows how displacement changes with distance at a certain time
wavelength would be measured normally
how do you model waves
how do you measure the velocity of ripples
how do you measure the velocity of sound
refraction
a wave travelling from one medium to another, velocity changing and ergo its direction
when the wave velocity changes…
velocity changes, wavelength changes
frequency stays the same
what is the normal
a line at 90 degrees to the surface
how does velocity affect refraction
at a high velocity, wave bends away from the normal
at a low velocity, wave bends towards normal
what happens to a sound wave at a boundary
reflected (echo)
transmitted (refracted)
absorbed
if densities on either side of boundary are very different, more of sound is reflected
ultrasound definition
sound with a frequency above 20,000 Hz
how to use ultrasound
how does your ear detect sound
why can we only hear a certain range of frequencies
speed of light
3 x 10^8 m/s
how do you produce and detect radio waves
uses for EM waves
which EM waves are dangerous and why?
how do lenses correct vision
mass of electron
0.0005
