Question

What's the equation to calculate the WIDTH of the slit in a DOUBLE slit experiment?

Answer 1

Just to clarify I'm not looking for the equation for slit separation, nor is this a single slit experiment problem.

Answer 2

The interference is wave phenomenon of light where the slit separation can be calculated from the fringe as the calculated formula dsin theta=n lambda

Answer 3

***Please read the first comment before answering. Thank you. ***

Answer 4

If you are asking for the width of each of the double slits then it goes as follows.

Each of the slits alone would produce a diffraction pattern the first minimum of which occurs at an angle given by \[\theta = \frac \lambda d\]
where lambda is the wavelength of the light and d is the slit width.

When the two diffraction patterns from the two slits overlap you get the double slit interference pattern (equally spaced bright fringes) with the brightness of these fringes modulated by the single slit diffraction pattern.

Here is link to see what the double slit interference pattern looks like:

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/dslit.html

and here is the analysis of the single slit diffraction pattern:

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/sinslit.html#c1

Answer 5

Do you know young's double slit experiment?

Answer 6

thanks @Farcher . finally understood