^Linear momentum of the EM wave
^Linear momentum of the EM wave
EM waves carry energy and momentum. If a portion of EM wave of energy U propagates with speed c, then linear momentum of the EM wave is ![]()
^Linear momentum of the EM wave
EM waves carry energy and momentum. If a portion of EM wave of energy U propagates with speed c, then linear momentum of the EM wave is ![]()
^Poynting vector
Poynting vector
gives intensity of EM – wave & is defined as:
SI unit : W/m2
^Intensity of EM waves
Intensity of EM wave is defined as the average energy crossing per second per unit area perpendicular to the direction of propagation of electromagnetic wave. i.e.


^Total energy density of EM waves
Total energy (u) of EM waves

,
^Magnetic energy density of EM waves
Magnetic energy density (uB) of EM waves is

^Electric energy density of EM waves
Electric energy density (uE) of EM waves is

^Speed of EM-waves
Speed of EM wave depends only upon the electric and magnetic properties of medium & is given by

^Equation of EM-waves
For an EM wave propagating along + X-axis is described by the mathematical functions
EY = E0 sin (ωt – kx), EX = 0 & EZ = 0 &
BZ = B0 sin (ωt – kx), BX = 0 & BY = 0

^Propagation of EM-waves
EM waves propagate such that E & B vectors
1. are always in phase
2. vary sinusoidally at right angles to each other as well as it right angles to direction of (DOP) & thus EM waves are transverse.
DOP is in the direction given by ![]()

^Deflection of EM-waves
EM waves are neutral, thus can’t be deflected by E & B fields.