# Light Interference Webassign question

1. Nov 29, 2008

### nickredsox

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

Light of wavelength 525 nm is used to illuminate normally two glass plates 26 cm in length that touch at one end and are separated at the other end by a wire of radius 0.03 mm. How many bright fringes appear along the total length of the plates?

2. Relevant equations

2*t=(m+1/2)*wavelength

3. The attempt at a solution
I thought t would be .6 since that would be the diameter. Then I solved for m and got 228. However webassign doesn't like this answer and im not really sure how to go about this problem

2. Nov 30, 2008

### Staff: Mentor

You solved for the maximum value of m, but realize that m starts at zero.

3. Nov 30, 2008

### nickredsox

im not really understanding because if i solve for t when m=0 if i plug it back in and solve for m im just going to get 0

4. Nov 30, 2008

### Staff: Mentor

You're missing my point. The values of m: 0, 1, 2, 3, 4... If the maximum value of m = 4 (pretend), then how many values of m are there?

5. Nov 30, 2008

### nickredsox

there would be five. so for my answer it should be one more than the answer i already got (228)?

6. Nov 30, 2008

### Staff: Mentor

That's what I would put.

7. Nov 30, 2008

### nickredsox

thank you a lot it worked