Exploring Huygens' Wave Theory of Light

[T@P]

i just learned this in physics, and i don't quite understand something:

according to Huygens, (i think) light is a ciruclar wave, and at everypoint on the wave there are wavelets. because there are so many ways for the wavelets to form, light takes every possible path from point a to point b. that parts sort of makes sense. then, all the really weird paths get cancelled, out and you are left with essentially a cone of light.

the above (if i got it right) sort of makes sense. but what doesn't is that this is supposed to explain why when you make a pinhole that's too small you get blurryness. shouldn't you just get the image to be not as bright? i don't quite see where the blurry part comes in.

 

[shyboy]

If you have a small pinhole, you can get a diffraction from opposite edges.
So, if you ahe a single source, you will get a bright central (main) peak and a lot of small peaks resulting from the diffraction. http://upload.wikimedia.org/wikipedia/en/e/e1/Diffraction1.png

The smaller the hole the stronger will be peaks. For a circular hole , I guess, you have additional rings. So your total image, produced by multiple sources will be blurred.

 

[Graeme Robinson]

Huygens' wave theory of light is a fundamental theory in the field of optics. It proposes that light is a transverse wave that travels through a medium, and that the wave is made up of smaller wavelets emanating from each point on the wave front. These wavelets interact with each other to produce the overall wave pattern that we observe.

As you correctly stated, according to Huygens, light takes every possible path from point A to point B. This means that the wavelets are interfering with each other, resulting in constructive and destructive interference. When all the wavelets are in phase and constructively interfere, we see a bright spot. However, when the wavelets are out of phase and destructively interfere, we see a dark spot.

Now, let's consider the example of a pinhole. When light passes through a small pinhole, it creates a diffraction pattern, which is a result of the wavelets interfering with each other as they pass through the opening. This diffraction pattern is what causes the image to appear blurry, as the wavelets are no longer in phase and are interfering with each other in a complex way. This is why a smaller pinhole results in a blurrier image, as the wavelets have more opportunity to interfere with each other.

In summary, Huygens' wave theory of light explains why light behaves in certain ways, such as diffraction and interference, and provides a deeper understanding of the nature of light. It is a complex theory, but it has been crucial in advancing our understanding of optics and light. I hope this helps clarify your understanding of the theory.