Waves

longitudinal pulse

particles of the medium move parallel to the direction of movement of the pulse

longitudinal waves

succession of longitudinal pulses

particles of the medium move parallel to the direction of propagation of the wave

compression

region of high pressure

rarefraction

region of low pressure

sound waves

3D longitudinal waves caused by vibrations that produce a regular variation in pressure in the medium

what do sound waves not travel through

vacuum

medium is necessary for propagation of sound

denser the medium

greater the speed of sound through medium

frequency

what human ear perceives as pitch

Hz

amplitude

human ear perceives as volume

dB

ultrasound

refers to sound waves at a higher frequency that we cant hear

uses of ultrasounds

treatment of sport injury

imaging in pregnancies

bats

boats

echoes

sound waves are reflected by large hard flat surfaces

used to calculate unknown distances

electromagnetic radiation

behaves like a wave when it travels and a particle when it interacts with other materials

dual nature of electromagnetic radiation

both wave and particle nature

wave nature of electromagnetic radiation

accelerating charges produce a continuously changing electric field which induces a continuously changing magnetic field at 90 degrees

electromagnetic wave is created

wave equation

c = f(lambda)

particle nature

electromagnetic radiation transfers energy in 'packets' called photons

photons

quanta that transfers energy to the particles of matter

have set amount of energy = quantum

quantum

invisible amount of physical quantity

quantisation

quantity comes in amounts that cannot be made smaller and smaller

greater the energy of the photon

higher the frequency and its penetrating ability and the shorter the wavelength

penetrating ability

refers to the ability to move through matter