Possible Difference in Light Paths for Coherent Sources at Point P?

In summary, the problem involves two coherent light sources emitting light of equal intensity and wavelength, and the intensity at point P is zero. The question is asking for the difference in path length taken by the light from each source in order to have interference and cancel each other out at point P. The diagram appears to be a triangle with two rays originating from the same point and meeting at point P. To have interference, one wave must travel a distance of half a wavelength more than the other. The given lengths of 4.3 cm and 5.1 cm are unclear in relation to the problem.
  • #1
jullrich
4
0

Homework Statement

: The diagram represents two coherent light sources emitting light of equal intensity and wavelength. The intensity of the light at point P is zero. Which of the following could be the difference in path length taken by the light in traveling from each source to point P?



Homework Equations

: the diagram looks like a 3-4-5 triangle with the short side left off and where to two lines cross for a point on the opposite side to be point P. The length of one side is 4.3 cm and the other side is 5.1 cm.



The Attempt at a Solution

: we know the answer is 1/2 lamda but have no idea how to how solve this ... please help

 
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  • #2
jullrich said:

Homework Statement

: The diagram represents two coherent light sources emitting light of equal intensity and wavelength. The intensity of the light at point P is zero. Which of the following could be the difference in path length taken by the light in traveling from each source to point P?



Homework Equations

: the diagram looks like a 3-4-5 triangle with the short side left off and where to two lines cross for a point on the opposite side to be point P. The length of one side is 4.3 cm and the other side is 5.1 cm.



The Attempt at a Solution

: we know the answer is 1/2 lamda but have no idea how to how solve this ... please help

Welcome to PF!

Do you know what is interference and what conditions must be applied for interference to occur?
 
  • #3
No interference and no conditions.
 
  • #4
What do you mean no interference? You haven't studied it or it isn't the case here?

Check out when waves interfere to cancel each other. To understand this, you must know how to plot a graph for a wave. And if you could upload the diagram (the actual one or sketched in paint), it would be a bit easier to discuss the exercise. Just remember that nobody will solve it for you. People will only give you hints to help you better understand the exercise and solve it yourself.
 
  • #5
The diagram looks like two rays from the same origin point.
The end of the rays would be the light itself.
 
  • #6
Well, you got me confused. At first you say that the diagram is a triangle but now you say that waves originate from the same point and meet at point P. For two waves two have an interference minimum (cancel out each other, hence have an intensity sum zero at an intersection point) they must be coherent and one must have the distance traveled by lamda/2 more. As much as I understand from your description of the exercise, this is what's asked. However, you have these 4.3 and 5.1 and I'm rather confused why.
 

1. What is the relationship between intensity and wavelength?

The intensity of a wave is directly proportional to its wavelength. This means that as the wavelength increases, the intensity also increases.

2. How does intensity affect the color of light?

The intensity of light can affect its perceived color. Higher intensity light tends to appear brighter and more vibrant, while lower intensity light may appear duller and less saturated.

3. What is the inverse relationship between intensity and wavelength?

The inverse relationship between intensity and wavelength means that as one increases, the other decreases. This means that as the wavelength increases, the intensity decreases and vice versa.

4. How are intensity and wavelength related to the energy of a wave?

The wavelength of a wave is inversely proportional to its energy. This means that as the wavelength increases, the energy decreases and vice versa. Intensity is also related to the energy of a wave, as higher intensity waves have more energy than lower intensity waves.

5. How does the intensity and wavelength of light affect its ability to cause damage?

Higher intensity and shorter wavelength light, such as ultraviolet and X-rays, have more energy and can therefore cause more damage to living organisms. Lower intensity and longer wavelength light, such as infrared and radio waves, have less energy and are less likely to cause damage.

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