Chapter-8|Electromagnetic Waves|NCERT 12th Physics:
Characteristics of Electromagnetic Waves:
1. Electromagnetic waves are produced by accelerated charge.
2. These waves do not required any material medium for propagation.
3. It travel with the speed of light.
4. Electromagnetic waves are transverse in nature.
5. The energy in electromagnetic waves is divided on an average, equally between electric and magnetic fields.
Ue= Um
6. The energy density(energy per unit volume) in an electric field E in vacuum is 1/2ε₀E² and that in magnetic field B is B²/2μ₀
Energy associated with an electromagnetic wave is
U= 1/2ε₀E² + B²/2μ₀
7. Electromagnetic waves being uncharged, are not deflected by electric and magnetic fields.
8. The electromagnetic waves like other waves, carries energy and momentum. Since it has momentum, an electromagnetic wave also exerts pressure called radiation pressure.
P= U/C
Electromagnetic waves also carry energy we can feel it by sunlight.