Electric Field and Magnetic Conversion

In summary, the solutions of a particular problem state that the average power <P> is equal to half the magnitude of the Poynting vector S, which is also equal to 1/(2μ0) multiplied by the square of the electric field E divided by the speed of light c. This does not mean that B is equal to E /(2μ0c), as the Poynting vector is defined as S = 1/μ0 * E x B and, for a wave in free space, the magnetic and electric fields are normal to each other and have a magnitude of B = 1/c * E. When taking a time average to calculate power, this relation simplifies to the first expression.
  • #1
onelastdance
6
0
In the solutions of a particular problem, it was stated that:

<P> = 1/2 |S| = 1/(2μ0) * E^2 / c

Where <P> is the average power, S is the Poynting vector.

From the above equation does that mean: B = E /(2μ0c) ?

I was just wondering how you can show the above relation between Magnetic and Electric field.
 
Last edited:
Physics news on Phys.org
  • #2
No it doesn't. The Poynting vector is [tex]\mathbf S=\frac{1}{\mu_0} \mathbf E \times \mathbf B[/tex]
and, for a wave propagating in free space, B and E are normal to each other (and to the direction of propagation) and have magnitude [itex]B = \frac{1}{c} E[/itex]. Look it up. When you take a time average to get power, it devolves to your first expression.
 
Last edited:
  • #3
Oh ok, thanks.
 
Last edited:

1. What is an electric field?

An electric field is a region in space where an electric charge experiences a force. It is created by electric charges and is represented by electric field lines.

2. What is a magnetic field?

A magnetic field is a region in space where a magnetic material experiences a force. It is created by moving electric charges and is represented by magnetic field lines.

3. How are electric and magnetic fields related?

Electric and magnetic fields are interrelated and can be converted into each other. A changing electric field creates a magnetic field, and a changing magnetic field creates an electric field. This phenomenon is known as electromagnetic induction.

4. What is the unit of measurement for electric and magnetic fields?

The unit of measurement for electric field is volts per meter (V/m), and the unit for magnetic field is tesla (T) or gauss (G).

5. How are electric and magnetic fields used in everyday life?

Electric and magnetic fields have various applications in our daily lives. They are used in electricity and magnetism-based technologies such as generators, motors, transformers, and electronic devices. They are also used in medical imaging, communication systems, and transportation systems.

Similar threads

Replies
14
Views
1K
Replies
3
Views
707
Replies
17
Views
1K
Replies
14
Views
2K
  • Electromagnetism
Replies
5
Views
1K
  • Electromagnetism
Replies
4
Views
978
Replies
11
Views
2K
Replies
4
Views
1K
Replies
1
Views
1K
Replies
2
Views
699
Back
Top