An instructor wishes to determine the wavelength of the light in a laser beam. To do so, he directs the beam toward a partition with two tiny slits separated by 0.195 mm. An interference pattern appears on a screen that lies 4.95 m from the slit pair.The instructor's measurements show that two adjacent bright interference fringes lie 1.59 cm apart on the screen. What is the laser's wavelength (in nm) ?