Diffraction

$1)$ Monochromatic light with wavelength $600$ nm is incident on a pair of thin slits. The distance between the slits is $\backslash (9\backslash$times $10^\{-6\}\backslash$mathrm$\{$~m$\}\backslash ).$ A screen is placed at $\backslash (\backslash$mathrm$\{$L$\}=3\backslash )$ meters from the screen.

a$)$ Find the maximum number of Bright fringes that will appear on the screen.

b$)$ What is the height from the center to the third BRIGHT fringe?

c$)$ If the wavelength is decreased do more, less, or the same number of fringes appear?

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