Electromagnetic Waves – Notes

Electromagnetic waves- features
Waves generally require a material medium for their propagation.
Electromagnetic waves can propagate in vacuum and in a medium.
Velocity of electromagnetic waves in a medium depends on the electric and magnetic properties of the medium.
Refractive Index of a medium= velocity of light in vacuum/velocity of light in the medium
One metre is defined as the distance travelled by light in vacuum in a time interval of 1/c seconds.
P=U/c

Electromagnetic waves – source and nature
Maxwell explained that the accelerating charges produce both an electric field and a magnetic field that varies with respect to time and these fields propagate in the form of a wave called “electromagnetic wave”.
According to the law of conservation of energy, the energy lost by the oscillating charge converts into the energy of the propagating wave.