Find Magnetic Field Amplitude from EM Wave Amplitude

In summary, the question asks for the amplitude of the accompanying magnetic field for a plane electromagnetic wave propagating in free space with a given electric field amplitude and frequency. The electric and magnetic fields have a special relationship in EM radiation and can be related using the frequency and amplitude values provided.
  • #1
tquiva
20
0

Homework Statement



A plane electromagnetic wave propagating in free space has an amplitude ([itex]\sqrt{3}[/itex]/2)a[itex]_{y}[/itex]-(1/2)a[itex]_{z}[/itex] V/m. Find the amplitude of the accompanying magnetic field assuiming the frequency of the electric field is 1 GHz.

Homework Equations



f[itex]_{E}[/itex] = f[itex]_{H}[/itex]

[itex]\frac{E_{0}}{B_{0}}[/itex] = [itex]\frac{ω}{k}[/itex] = c

The Attempt at a Solution



I know that the frequency for both the Electric and Magnetic fields are equivalent. Therefore, the magnetic field frequency is also 1 GHz.

However, the question says "electromagnetic wave." This term means the cross product result or E x B right? With that being said, I'm not sure how to obtain the amplitude of the magnetic field if I don't have any info for the electric field.

Or is there some other equation related to the EM wave?

Any help or suggestions is greatly appreciated!
 
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  • #2
tquiva said:
..., the question says "electromagnetic wave." This term means the cross product result or E x B right? With that being said, I'm not sure how to obtain the amplitude of the magnetic field if I don't have any info for the electric field.
But you are provided with "info for the electric field": the frequency and the amplitude. What else do you need?

For EM radiation the E and B components have a special relationship.
 
  • #3
tquiva said:

Homework Statement



A plane electromagnetic wave propagating in free space has an amplitude ([itex]\sqrt{3}[/itex]/2)a[itex]_{y}[/itex]-(1/2)a[itex]_{z}[/itex] V/m.

Perhaps it was meant the vector amplitude of the electric field.

ehild
 

1. How is the magnetic field amplitude related to the EM wave amplitude?

The magnetic field amplitude is directly proportional to the EM wave amplitude. This means that as the EM wave amplitude increases, the magnetic field amplitude also increases.

2. What is the formula for calculating the magnetic field amplitude from the EM wave amplitude?

The formula for calculating the magnetic field amplitude from the EM wave amplitude is B = |E|/c, where B is the magnetic field amplitude, E is the EM wave amplitude, and c is the speed of light in vacuum.

3. Is there a difference between the magnetic field amplitude and the magnetic field strength?

Yes, there is a difference between the magnetic field amplitude and the magnetic field strength. The magnetic field amplitude refers to the maximum value of the magnetic field, while the magnetic field strength refers to the intensity or magnitude of the magnetic field at a specific point in space.

4. How does the magnetic field amplitude affect the behavior of an EM wave?

The magnetic field amplitude plays a crucial role in determining the behavior of an EM wave. It affects the propagation, polarization, and energy of the wave, and also influences how the wave interacts with matter.

5. Can the magnetic field amplitude be measured directly?

No, the magnetic field amplitude cannot be measured directly. It can only be calculated or inferred from other measurable quantities, such as the EM wave amplitude or the magnetic field strength.

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