In a double-slit interference experiment, the wavelength is λ = 432 nm, the slit separation is d = 0.100 mm, and the screen is d = 42.0 cm away from the slits. what is the linear distance between the 8th order maximum and the 4th order maximum on the screen?

In the double-slit interference experiment, the distance of the nth-maximum from the center of the screen is given by

where
is the wavelength
D is the distance between the screen and the slits
d is the distance between the slits

In our problem, 




By applying the previous formula, we can calculate the distance of the 4th maximum from the center of the screen:


Similarly, the distance of the 8th- maximum is


Therefore, the distance between the two maxima is

Idont understand the question