Red light from three separate sources passes through a diffraction grating with 6.60×105 slits/m. the wavelengths of the three lines are 6.56 ×10−7m (hydrogen), 6.50 ×10−7m (neon), and 6.97 ×10−7m (argon). part a calculate the angle for the first-order diffraction line of first source (hydrogen). express your answer using three significant figures.

· Visible light passes through a diffraction grating that has 900 slits per centimeter, and the interference pattern is observed on a screen that is 2.74 m from the grating. In the first-order spectrum, maxima for two different wavelengths are separated on the screen by 3.16 m. What is the difference between these wavelengths? . I know to apply the equation din(theta) = m*wavelength but I'm not sure how to find all the missing variables or to get the difference in wavelengths

snell's law

refractve index = sin incidence / sin refraction