Wave Optics

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

A board has two small slits separated by a small distance d. A light ray of a certain wavelength is shone through the holes. A screen is placed in front of the holes and bright fringes are displayed on it. If the light wavelength is 440 nm, the distance between the slits is 4000 nm and the distance between the slits and screen is one meter then how wide would the screen have to be so that the third order fringes just hit its left and right sides?

128 cm
14.2 cm
17.5 cm
66.0 cm
38.3 cm

2. Relevant equations

m*LAMBDA = d * y/L

3. The attempt at a solution

The equation that wrote is the one that I think that I should use, but I am stuck.

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

A board has two small slits separated by a small distance d. A light ray of a certain wavelength is shone through the holes. A screen is placed in front of the holes and bright fringes are displayed on it. Which of these actions would triple the distance between the zero order and first order bright fringes on the screen?

triple the distance between the slits
triple the distance between the slits and screen
double the distance between the slits
double the distance between the slits and screen
double the wavelength of the light

2. Relevant equations

3. The attempt at a solution

I could figure this one out if I knew the equation used
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
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 Recognitions: Gold Member Homework Help You have the right equation. Why are you stuck?
 In the first question I posted, the part that says: "how wide would the screen have to be so that the third order fringes just hit its left and right sides?" wavelength = 440nm m = 2 d = 4000nm L = 1 m solve for y?

Recognitions:
Gold Member
Homework Help

Wave Optics

Yes, solve for y. But you want m=3, don't you?
 Yep...my mistake :D On my 2nd question....does it use the same equation? If so, "triple the distance" is that referring to d or L?
 Recognitions: Gold Member Homework Help I think you would use the same equation. In the question, triple the distance refers to y, the distance on the screen between the zero order and first order bright fringes.
 Thanks a lot...all your help is appreciated....this is what happens when you take physics as an online course :D