Magnetic field from electric field given a function of time

In summary, the conversation discusses an electromagnetic wave in free space with an electric field vector given by E = f(t-z/c0)x, where x is a unit vector in the x direction and f(t) = exp(-t2/τ2)exp(j2πv0t). The physical nature of the wave is discussed, including its polarization, direction of propagation, and amplitude. The magnetic field vector is also determined through the use of Maxwell's equations.
  • #1
crazycool2
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Homework Statement


An em wave in free space has an electric field vector E = f(t-z/c0)x where x is a unit vector in the x direction and f(t)= exp(-t22)exp(j2πv0t). Describe the physical nature of this wave and determine an expression of the magnetic field vector.

Homework Equations


Maxwells faradays law ∇XE=-μ δH/δt

3. The Attempt at a Solution [/B]
I have two things I´m not so sure about. Given f(t) will the electric field now become
E= exp(-(t-z/c0)22)exp(j2πv0(t-z/c0))x

If so, when I use the curl of the field (dEz/dy-dEy/dz)x+(dEx/dz-dEz/dx)y+(dEy/dx-dEx/dy)z
I assume everything is 0 except for dEx/dz which I´m not sure because it´s multiplied by a unit vector y.
when I derivate by z I then have to intergrate by on both sides of the max eq. but I get a very complex integral.
So where I did I get lost.
Thanks in advance.
P.S. Describing the physical nature of this wave? Do I need to state that the wave is linaear homogenous and Isotropic.
 
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  • #2
Hi. For the physical nature of the wave, you can ask yourself: is it polarized, and if yes in which direction? is it propagating, and if it is in which direction? how is the amplitude: constant or changing?
For the B field, you can start by determining the charges and currents present. Then you should be able to use Maxwell's equations to determine a simpler relation between E and B...
 
  • #3
Scratch the second part of my answer, you can actually use ∇ × E = –μ ∂B/∂t directly, as you started:
the curl is easy to take, then integrating with respect to time becomes easy as well since t and z/c0 enter in the equation in (anti-)symmetric way...
 

FAQ: Magnetic field from electric field given a function of time

1. What is the relationship between magnetic field and electric field?

The relationship between magnetic field and electric field is described by Maxwell's equations. These equations state that a changing electric field will induce a magnetic field, and a changing magnetic field will induce an electric field.

2. How is the magnetic field from an electric field calculated?

The magnetic field from an electric field can be calculated using the Ampere-Maxwell law, which states that the curl of the magnetic field is equal to the current density plus the rate of change of the electric field over time.

3. What is the direction of the magnetic field from an electric field?

The direction of the magnetic field from an electric field is perpendicular to both the electric field and the direction of current flow. This is known as the right-hand rule.

4. How does the magnetic field from an electric field change over time?

The magnetic field from an electric field changes over time as the electric field changes. This is because the magnetic field is induced by the changing electric field. As the electric field changes, the magnetic field will also change in magnitude and direction.

5. Can the magnetic field from an electric field be manipulated or controlled?

Yes, the magnetic field from an electric field can be manipulated or controlled by changing the electric field. This is the basis for technologies such as electromagnets and electric motors, which use the relationship between electric and magnetic fields to produce desired effects.

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