Physics
posted by Chelsea on .
Light containing two different wavelengths passes through a diffraction grating with 1300 slits/cm. On a screen 16.0 cm from the grating, the thirdorder maximum of the shorter wavelength falls midway between the central maximum and the first side maximum for the longer wavelength. If the neighboring maxima of the longer wavelength are 8.44 mm apart on the screen, what are the wavelengths in the light? (Hint: Use the small angle approximation.)

1/130000 * sinTheta=1*lambda
but sinTheta=tantheta=8.44/160
now solve for lambda, in m