Question about double-slit experiment

kuruman said:

If you use a laser of higher intensity the locations where bright fringes appear will receive more photons per second so they will be brighter.

Why do you think that increasing the wavelength will increase he number of bright fringes? What equation do you have in mind? Also, in what way do you think the experiment will be improved if you increase the number of bright fringes?

Jason Ko said:

The diffraction effect will enhance as the wavelength has increased, so the bright fringes will span wider. If the number of bright fringes has increased, the measurement will be more accurate.

kuruman said:

I repeat, what mathematical equation says that the number of fringes increases as the wavelength increases? You need to understand this point before you start thinking about increasing the accuracy of the experiment.

Also, you did not explain why more fringes means more accurate measurement. What exactly will you be measuring that will have its accuracy increased when you have more bright fringes?

Jason Ko said:

I think I've made thing wrong. mλ=asinθ, larger wavelength means larger θ, so fewer fringes will be formed.

kuruman said:

Now you got the idea. So if you want to have more fringes, you have to decrease the wavelength.