I missed a day of class the other day so I dont have any notes on how to do this. If someone could please give me some tips or a site that helps explain how to do problems like these it would be greatly appriciated. Violet light falls on two slits separated by 1.92 10-5 m. A first-order line appears 13.1 mm from the central bright line on a screen 0.611 m from the slits. What is the wavelength of the violet light? I have about 10 problems do tomarrow very similar to this one and not a clue how to do them.