What is the fringe spacing equation used to calculate the distance between fringes in an interference pattern?

The fringe spacing equation used to calculate the distance between fringes in an interference pattern is:

textFringe Spacing fraclambda cdot Dd

Where:

• Fringe Spacing is the distance between adjacent fringes
• (lambda) is the wavelength of the light
• D is the distance between the slits and the screen
• d is the distance between the two slits or sources of light