# Homework Help: Young's double slit experiment question.

1. Jul 2, 2007

### Mr Virtual

Hi
I don't know whether this is a homework-type question or not, so I am posting it here.

In young's double slit experiment the interference pattern is found to have an intensity ratio between bright and dark fringes as 9. What does this imply:
(Below are the options provided in the book. One of them is the correct answer)
1. the intensities at the screen duo to the two slits are 5 nd 4 units respectively
2. the intensities at the screen are 4 units and 1 unit respectively
3. the amplitude ratio is three
4. The amplitude ratio is two

What is the correct answer?

As far as I think, option 3 is correct, because if amplitude ratio is 3, then probability ratio will automatically be (amp^2)=3^2=9.
Am I right?

Mr V

2. Jul 2, 2007

### G01

The intensity is proportional to the amplitude squared so I would agree with you. I would also pick #3.

Last edited: Jul 3, 2007
3. Jul 2, 2007

### nrqed

I know this is just a typo but just to make sure that it does not cause confusion for the OP, G01 meant to say that the intensity is proportional to the amplitude squared.

sorry, it's just a tiny detail and I know that G01 knows that.

Cheers

4. Jul 3, 2007

### Mr Virtual

Thanks a lot.

Mr V

5. Jul 3, 2007

### G01

Thanks for pointing it out. I have fixed the typo in my above post.