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- Thread starter Arup Biswas
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BvU

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Because of destructive interferencejust answer "Why we get a dark 'fringe'?

depends on the source of the interfering waves.'Fringe'???" Shouldn't we get a pattern like the the dark 'point' or 'line'

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Your post his highly confusing and very difficult to follow. It is hard to distill exactly what you are asking.

Due to that, I will tackle what you wrote in the title of the thread. The answer to "What is actually wave?" (sic) is actually quite simple. It is any system that can be written down in the form of the mathematical wave equation.

Everything else, such as "dark fringes", etc...etc., are

This is why in physics, practically every single concepts and ideas have strong underlying mathematical description. It isn't just words. Rather, those words are accompanied by mathematical formulations. Each time we utter the words such as "Oh, it is a wave", we all know and are aware of what that entails, and all the mathematical and physical rules and consequences.

Zz.

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CWatters

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Do we have the right pictorial diagram of a wave?

Yes. Compare the pictorial diagram with a wave on the open sea.

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sophiecentaur

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Hi. I can tell that English is not your first language but well done for trying.

Here is a simple, general description of what we mean by a 'Wave"

A wave describes how a disturbance of any kind propagates through a medium and this is NEVER instantaneous. There is always some delay between a change in one thing (say the blip of a loudspeaker cone) and what happens to your ear drum. The pulse of pressure travels through the air from molecule to molecule and we describe that as a wave. A continuous wave can be produced by a loudspeaker or a radio transmitter etc etc. and the there can be several waves travelling to your ear. If they are at the same frequency then they can augment or cancel at the location of your ear.

This effect of addition and cancellation is general for all waves. Once it has been launched, the energy is never 'lost' but redirected from some regions (nulls) to others (maxima), which produces "fringes" of loud and quiet , light and dark, good and bad TV reception etc.

What else you need will depend on your level of Science of Maths understanding.

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Khashishi

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##\frac{\partial^2 u}{\partial t^2} = c^2 \nabla^2 u##

(Sometimes a generalized wave equation might be used)

Some solutions are

##\sin(k.x-\omega t), \cos(k.x-\omega t), e^{i(k.x-\omega t)}##. Since the (homogeneous) wave equation is linear, any sum of solutions to the wave equation is another solution. So you can get fairly complicated waves. You can have propagating waves or standing waves or something in between.

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