Question

In a single-slit diffraction pattern on a flat screen, the central bright fringe in 1.0 cm wide when the slit width is 4.70 10-5 m. When the slit is replaced by a second slit, the wavelength of the light and the distance to the screen remaining unchanged, the central bright fringe broadens to a width of 2.4 cm. What is the width of the second slit? It may be assumed that è is so small that sin è = tan è