If the distance between the slits in a double-slit apparatus is increased, while the width of each slit is kept the same, the number of interference fringes within the central diffraction maximum will
A) decrease.
B) increase.
C) remain the same.
D) may do any of the above.

Question

Quizplus · Accepted Answer

Increasing the distance between the slits in a double-slit apparatus causes the interference fringes to spread out more, effectively reducing the number of fringes within the central diffraction maximum. This is because the fringe spacing is inversely proportional to the slit separation.

If the Distance Between the Slits in a Double-Slit Apparatus