# Electromagnetic Waves

1. Apr 25, 2010

### abpandanguyen

1. The problem statement, all variables and given/known data
1.The magnitude of the electric field between the two circular parallel plates is
E = (4.0 x 105 ) - (6.0 x 104 t), with E in volts per meter and t in seconds. At
t = 0, the field is upward. The plate area is 4.0 x 10-2 m2. For t > 0,

a) what are the magnitude and direction of the displacement current between
the plates, and
b) is the direction of the induced magnetic field clockwise or counterclockwise
around the plates?

2. Relevant equations
not too sure but...
Id = (ε₀)(times the change in electric flux)

Gauss's Law (didn't really know how to write this out sorry >_<)
Magnetic Field times the integration of the electric field is equal to charge over ε₀

Maxwell Ampere Equation
Magnetic Field times the integration of the magnetic field = (permeability of free space)(enclosed current)
3. The attempt at a solution

My understanding of these questions is very bad at the moment. I am not sure where to even begin.

My current attempt is taking the derivative the Electric field equation given then using that to determine the displacement current using the first equation. After that I am trying to use the Rhr (right hand rule) to determine the direction of the magnetic field and I got counter clockwise because of the relationship between magnetic field and electric field in the maxwell ampere equation. Help please >_<