A Thin Beam of Light of Wavelength 625 Nm Goes

Short Answer

A thin beam of light of wavelength 625 nm goes through a thin slit and falls on a screen 3.00 m past the slit. You observe that the first completely dark fringes occur on the screen at distances of ±8.24 mm from the central bright fringe, and that the central bright fringe has an intensity of 2.00 W/m² at its center.
(a) How wide is the slit?
(b) What is the intensity of light at a point on the screen that is one-quarter of the way from the central bright fringe to the first dark fringe?