Everything You Need To Know About Electromagnetic Waves

Share this Content

Before we start our today’s topic let’s talk about the topic first. I mean-

What are E.M waves?

If there exists a variable electric field and magnetic field in any place, then it spreads around like a wave called Electromagnetic Wave.

Properties of E.M waves:

  1. E.M waves are formed by accelerated ionized particles.
  2. No medium is required for the propagation of E.M waves.
  3. The velocity of E.M waves = velocity of light
  4. In free space velocity of E.M waves ⇒C=1/√𝜇0𝝐0
  5. In any other medium velocity of E.M waves ⇒v=1/√𝜇𝝐
  6. E.M waves follow the principle of superposition.
  7. In free space relation between E and B is, c=E/B
  8. When E.M waves propagate they carry energy with them. This energy is equally divided into an electric field and a magnetic field.

Scientist Maxwell expresses the four basic laws of electricity and magnetism with the help of four equations. The laws are-

  1. Gauss law for static electricity
  2. Gauss law for magnetism
  3. Faraday’s law for electromagnetic induction and
  4. Maxwell-Ampere rotation law

Now the equations are-

  1. âˆĢE.ds=q/𝝐0 {E & ds are vector quantity}. It is independent of time and equally applicable for static and dynamic charges. From this equation, it comes to know that the electric force line is not a closed curve.
  2. âˆĢB.ds=0 {B & ds are vector quantity}.It is also independent of time. From this equation, it comes to know that the existence of a single magnetic pole is not possible and the magnetic force line is a closed curve.
  3. âˆĢE.dl= -d/dt(âˆĢB.ds) . It depends on time. According to this equation, the path integration of the electric field in a closed path is equal to the change in electric flux in that path.
  4. âˆĢB.dl=𝜇0{I+đœē0(d𝜑E/dt)} .{đœē0(d𝜑E/dt)=iD(displacement current)} It is also depend on time. From this equation, we can conclude that changing the electric fields can produce a magnetic field.

Now it’s time to some important points,

  1. If light propagating in x-direction it can be written as E=E0(𝜔t-x/c) &B=B0(𝜔t-x/c) { B0 =amplitude of magnetic field, E0 = amplitude of electric field, 𝜔 = angular frequency}
  2. Radiation pressure: It is exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. Radiation pressure, p=(2I/c)r+ (I/c)(1-r) {r=reflection coefficient}
    p=I/c ; for complete absorption
    p=2I/c ; for complete reflection
  3. The energy density of electromagnetic field: u= 𝝐0E2/2 + B2/2𝜇0
  4. Average energy density = 𝝐0E2/2 = B2/2𝜇0

These are the basic things you have to know in this chapter.

Hope this information helps you, if yes then don’t forget to subscribe to our newsletter to get regular updates.

Share this Content
Snehasish Konger
Snehasish Konger

Snehasish Konger is the founder of Scientyfic World. Besides that, he is doing blogging for the past 4 years and has written 400+ blogs on several platforms. He is also a front-end developer and a sketch artist.

Articles: 186

Newsletter Updates

Join our email-newsletter to get more insights

Leave a Reply

Your email address will not be published. Required fields are marked *