Electromagnetic waves waves review

In summary, the conversation discusses a plane electromagnetic sinusoidal wave with a wavelength of 56.0 m and an electric field amplitude of 20.0 V/m. The frequency of the wave is calculated to be 5.35 x 106 Hz using the equation f = c/λ. The magnetic field when the electric field has its maximum value in the negative y direction is also determined. Finally, an expression for the wave is written in the form B = Bmax cos(kx - ωt), with numerical values for Bmax, k, and ω.
  • #1
Color_of_Cyan
386
0

Homework Statement


The figure below shows a plane electromagnetic sinusoidal wave propagating in the x direction. Suppose the wavelength is 56.0 m and the electric field vibrates in the xy plane with an amplitude of 20.0 V/m.

34-p-013.gif
(a) Calculate the frequency of the wave.

(b) Calculate the magnetic field when the electric field has its maximum value in the negative y direction.

(c) Write an expression for with the correct unit vector, with numerical values for Bmax, k, and ω, and with its magnitude in the form
B = Bmax cos (kx − ωt).
(Assume B is measured in nT, x is measured in m and t in s.)

Homework Equations



c = 1/(μ0ε0)1/2

c = 299609581 m/s

f = c / λ

E = Emax cos(kx - ωt)

B = Bmax cos(kx - ωt)

E max / B max = E / B = ck = 2π/λ

ω = 2πf

The Attempt at a Solution



I only found the frequency, which is 5.35 x 106 HzI would like some hints how to find E max then I can just use the third equation listed.I'm thinking that E = Emax cos(kx - wt) and I think

E = (20V/m) cos[(0.1121)(x) - (33615041)(t)]

where 0.1121 is k (k=2pi / λ)

and where 33615041 is ω (ω = 2πf)
What would I do with regards to x and t in the equation?
 
Physics news on Phys.org
  • #2
The amplitude of the wave is given to you, and that is the magnitude of the electric field when it is maximal, isn't it?

Edit: wait, why are you asking about [itex]E_\text{max}[/itex] when you already observed it's [itex]20 \; \text{V/m}[/itex]
 
  • #3
I didn't really see that... thanks

I got the rest of the problem as well.
 
Last edited:

1. What are electromagnetic waves?

Electromagnetic waves are a type of energy that consists of both electric and magnetic fields. They are produced by the movement of electrically charged particles and can travel through space at the speed of light.

2. What are the different types of electromagnetic waves?

The different types of electromagnetic waves are radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. These waves have different wavelengths and frequencies, which determine their properties and uses.

3. How do electromagnetic waves interact with matter?

Electromagnetic waves can interact with matter in different ways depending on the properties of the material. They can be reflected, absorbed, transmitted, or refracted. The interaction of waves with matter is what allows us to see, hear, and use various forms of technology.

4. What are the applications of electromagnetic waves?

Electromagnetic waves have many practical applications, including communication (radio and television), cooking (microwaves), heating (infrared), medical imaging (X-rays), and sterilization (UV radiation). They are also used in scientific research and technology development.

5. Are electromagnetic waves harmful?

Electromagnetic waves can be harmful at high levels of exposure, such as in the case of X-rays and gamma rays. However, most forms of electromagnetic waves, including visible light and radio waves, are not harmful to humans. The potential harm of exposure to electromagnetic waves depends on factors such as intensity, duration, and frequency.

Similar threads

  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
875
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
831
  • Introductory Physics Homework Help
Replies
5
Views
3K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
703
  • Introductory Physics Homework Help
Replies
1
Views
4K
  • Introductory Physics Homework Help
Replies
10
Views
4K
Back
Top