# Homework Help: Intefrence of light and separation of slit

1. Aug 24, 2014

### desmond iking

1. The problem statement, all variables and given/known data
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 cant understand

2. Relevant equations

3. The attempt at a solution

2. Aug 24, 2014

### 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?

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 ...

3. Aug 25, 2014

### 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 cant understand

4. Aug 25, 2014

### 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.