Energy in Electromagnetic Waves Electromagnetic waves transport energy. This problem shows you which parts of the energy are stored in the electric and magnetic fields, respectively, and also makes a useful connection between the energy density of a plane electromagnetic wave and the Poynting vector In this problem, we explore the properties of a plane electromagnetic wave traveling at the speed of light calong the x axis through vacuum. Its electric and magnetic field vectors are as follows E=E0 sin (ka -wt)3. B = B0 sin (kx-wt) k Throughout, use these variables (E, B, Eo, Bo, k, x, and w) in your answers. You will also need the permittivity of free space eo and the permeability of free space 140 Note: To indicate the square of a trigonometric function in your answer, use the notation sin(x)A2 NOT sinA2(x)

Instantaneous Energy Electric Field = ue(t)= ε₀(E₀*sin(kx-wt))²/2

Instantaneous Energy Magnetic Field = ub(t)= B₀(E₀*sin(kx-wt))²/2μ₀

Average Energy Density  of electric field of the wave = E₀² ε₀/4

Average Energy Density  of Magnetic field of the wave <ub>= B₀²/4μ₀

The Poynting Vector = S = ε₀*c*E₀²/2x

Explanation:  The relationship between μ₀ and ε₀ is

                                                  μ₀= 1/ε₀c²

To Poynting flux definition is provided in the image.

Average Density of the whole wave could then be found by:

                                         <u> =(E₀² ε₀/4)+ (B₀²/4μ₀)

To get to a better answer you can subsitute the relationship between μ₀ and ε₀

Remember: c = the speed of light in vacuum = 3.0 * 10⁸ m/s                    

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

d. platinum would have the greatest temperature increase because it has the lowest specific heat.