what is a progressive wave

a wave that travels through matter (or in some cases a vacuum) and transfers energy from A to B but not matter

equation for velocity of a wave

v=f(lamda)

equation for frequency

f=1/T

what is intensity proportional to

amplitude^2

what are coherent waves

waves emitted from two sources that have constant phase difference

when two waves superpose what happens

at points in phase, constructive interference

at points out of phase, destructive interference

how are stationary waves created

reflected wave superposes

antiphase points create nodes with zero displacement

in phrase points create antinodes with max displacement

distance between node and antinode = half wavelength

when two waves interfere to create interference patterns, where are maxima and minima formed?

when path difference is an integer multiple of wavelength then a maxima is formed

when path difference in (n+1/2)(lamda) then a minima is formed

path and phase difference at central maxima

0 and 0

path and phase difference at first order minima

1/2 lamda and pi

path and phase difference at first order maxima

lamda and 2pi

what is the fundamental frequency

the minimum frequency for a standing/stationary wave

equation for youngs double slit experiment

lamda=ax/D a=slit separation D=distance between slits and board showing interference pattern x=separation between fringes

in reflection what angle equals what angle

angle of incidence = angle of reflection

equation for refractive index

n=c/v c=speed of light 3X10^8

v= speed of light through material

refraction law equation

n1sin(x1)=n2sin(x2)

x=angle between ray and normal

what is refraction

occurs when a wave changes direction as it changes speed when passing from one medium to another

what is diffraction

the spreading out of a wave when it passes through a gap or around an obstacle.

when does maximum diffraction occur

when the gap is the same size as the wavelength of the wave

what is polarisation

when particles oscillate in one plane/direction

what is the intensity of a progressive wave?

the radiant power passing through a surface per unit area

equation for intensity

I=P/A

equation for intensity radiated from a sphere

I=P/4(pi)r^2

order of EM

Red midgets interfere very usually xylophone gigs

radio, micro, infra, visible, ultra, xray, gamma

in this order how does frequency and wavelength change

frequency increases

wavelength decreases

wavelength of radio waves

10^6 to 10^-1

wavelength of microwaves

10^-1 to 10^-3

wavelength of infrared

10^-3 to 700nm

wavelength of visible

700nm to 400nm

wavelength of ultraviolet

400nm to 10^-8

wavelength of xray

10^-8 to 10^-13

wavelength of gamma

10^-10 to 10^-16

equation for frequency of em

f=c/lamda

conditions for total internal reflection

light must be travelling in a medium with a higher refractive index and strike a boundary with a medium of lower refractive index

angle at which it meets boundary must be bigger than the critical angle

equation to find critical angle

sinc=1/n

total internal reflection critical angle with prism

sinc=n2/n1