Breaking EM Destructive Interference

In summary, destructive interference occurs when two waves with opposite phases cancel each other out, resulting in a null field. However, it is not possible to have destructive interference everywhere in space, as there will always be areas of constructive interference. The term "destructive interference" is a bit misleading, as the energy is actually being redirected rather than destroyed. This can be useful in applications such as frequency-selective coatings on glass.
  • #1
MTtylerb
3
0
Hi, I have a question about destructive interference. Suppose I have two very closely spaced EM sources, e.g two RF emitters. At a point far away from the sources the arbitrarily orientated magnetic field due to source one is: B1(t)=sin(ωt) and source two: B2(t)=sin(ωt+pi) so the total field is null due to destructive interference B(t)=B1(t)+B2(t)→0 (the same is true for the electric fields). Is there anyway to extract energy from the nonzero energy wound up in the individual fields? Or does destructive interference of the two fields make this impossible?
 
Science news on Phys.org
  • #2
Hi MTtylerb, welcome to PF!

You can extract energy from the field at other locations, just not from the locations where there is complete destructive interference.
 
  • #3
What if the interference occurs everywhere in space?
 
  • #4
MTtylerb said:
What if the interference occurs everywhere in space?

This is not possible, there must be areas with constructive interference.
 
  • #5
How about two infinitely long solenoid coils wound in between another but with opposing currents? The net fields throughout space would be null as it is composed of the non-zero individual fields.
 
  • #6
If you wind them in between one another then you will still have regions of constructive superposition. It is simply impossible to have destructive interference everywhere in space.
 
  • #7
The term "destructive interference" can be misleading when you are talking about energy. A better name might be "energy redirection". The fields of the waves add together mathematically to destroy each other at certain points, but there is no actual physical destruction happening. The energy is redirected. (Waves can destroy objects, such as a laser cutter, but this is through high-energy absorption, not through wave interference.) This energy redirection can be quite useful. For example, frequency-selective coatings on glass can be made using interference. Certain frequencies are reflected instead of transmitted.
 

1. What is destructive interference?

Destructive interference is a phenomenon where two waves with identical frequencies and opposite amplitudes cancel each other out, resulting in a decrease in the overall amplitude of the resulting wave.

2. How does destructive interference occur?

Destructive interference occurs when two waves meet and their amplitudes are out of phase, meaning they are at opposite points in their cycles. When this happens, the peaks of one wave line up with the troughs of the other, resulting in cancellation of the waves.

3. What is the importance of understanding destructive interference?

Understanding destructive interference is important in various fields such as acoustics, optics, and radio waves. It helps explain the behavior of waves and how they interact with each other, which is crucial in designing and optimizing technologies that rely on wave properties.

4. How is destructive interference different from constructive interference?

Destructive interference involves two waves canceling each other out, resulting in a decrease in amplitude. On the other hand, constructive interference occurs when two waves with identical frequencies and amplitudes combine to form a wave with a larger amplitude.

5. Can destructive interference be controlled or prevented?

Destructive interference cannot be controlled or prevented, as it is a natural phenomenon that occurs when two waves meet. However, it can be minimized by using techniques such as adjusting the phase and amplitude of the waves or using materials that absorb or reflect waves.

Similar threads

  • Introductory Physics Homework Help
Replies
7
Views
1K
Replies
6
Views
5K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Replies
11
Views
2K
Replies
8
Views
2K
  • Quantum Physics
Replies
1
Views
963
  • Astronomy and Astrophysics
Replies
23
Views
5K
Back
Top