Intefrence of light and separation of slit

[desmond iking]

Homework Statement

according to my notes, if the single slit is made larger , the slit can can been as point source, where each point can produce its own set of intefrence pattern. whi is it so ? i can't understand

Homework Equations

The Attempt at a Solution

 

[BvU]

Hi Des,
Try to read what you write before posting. What's this about ?

Why is what so? It is so because you wrote it down, but that's not what you are after, right?

Perhaps instead of

if the single slit is made larger , the slit can can been as point source, where each point can produce its own set of intefrence pattern

it should have been something like

... each point in the opening can be seen as a point source that contributes to form an interference pattern ...

 

[desmond iking]

sorry. i typed too fast .
according to my notes, if the single slit is made larger , the slit can be seen as point source, where each point can produce its own set of inteference pattern. why is it so ? i can't understand

 

[BvU]

It is not so. A slit is not a point source and cannot be seen as such: it is an extended source.

The word Interference has "inter-" in it, as in Latin inter (prep., adv.) "among, between, betwixt, in the midst of" (or as in "Internet", nowadays: also between senders and receivers). It takes two to tango and it takes more than one point source before one can speak of interference.

Each point of the slit acts as a point source (see Huygens principle) and the waves emanating from these points form an interference pattern.