# Why does increasing distance from the double slit in Young's experiment increase the separation between the fringe pattern?

I don't understand what equation deals with this.

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Related (and may be be a possible dupe): physics.stackexchange.com/questions/203979/… and links therein. – MAFIA36790 May 20 at 12:51

As a diagram screen $A$ is closer than screen $B$ and so the fringes are closer on screen $A$:
Fringe separation $\Delta x = \dfrac {\lambda \; D}{d}$ where $d$ is the slit separation, $\lambda$ is the wavelength of light and $D$ the distance from the slits to the screen.