Define progressive wave
wave in which energy is carried from one point to another by means of vibration or oscillations within the wave ,without transporting matter.
Types of waves
Transverse: mechanical & em
vibrations are open particular to the direction of transfer of energy of the wave
Longitudinal: mechanical
Vibrations are parallel to direction of transfer of energy of wave
requires matter
Electromagnetic spectrum
Radio waves >10cm
Microwave 1mm - 10cm
Infrared 700nm-1mm
Visible 400nm - 700nm
Ultraviolet 1mm-400nm
x-ray 1pico m to 1mm
gamma rays 1fm to 1picom
Characteristics of wave
displacement: distance in the specific direction point on the wave from its equilibrium position
Amplitude: maximum displacement of any point on the wave from equilibrium position
Period: Time take for one complete oscillation of point in a wave
Frequency: number of oscillations per unit time of a point on the wave
Wavelength: minimum between any two points of the wave with the same phase at the same instant
Wave speed: speed which energy transmitted by wave
Wave front: joining points which are in phase
Ray: direction in which energy of wave is travelling, always perpendicular to wave front
What can derive from different graph?
displacement-distance (all particles at certain time)
: wavelength
displacement-time (one particle across all time)
:period
Phase difference
how much one wave is out of step with another
Anti face when phase difference equals pi
Define intensity and it’s related formulas
intensity of a wave is powered transferred by a wave per unit area
Energy/Time x area =P/area
since I proportion to E
and E proportion to f^2 xo^2
I proportion to A^2
in 3d, I proportion to 1/r^2
in 2d, I proportion to 1/r
characteristics of polariser
Passes hundred percent of incident, light, polarised, parallel, to polarising axis and blocks completely all light polarised perpendicular to this axis
passes 50% incident unpolarised light
I = 1/2Io
only transferred wave
Maus Law
If incident light passing through analyses is already linearly polarised,
I= Iocos^2theta
Longitudinal waves cannot be polarised as they don’t have oscillation in plane normal to direction of transfer of energy of wave
