Achemist identifies compounds by identifying bright lines in their spectra. she does so by heating the compounds until they glow, sending the light through a diffraction grating, and measuring the positions of first-order spectral lines on a detector 15.0 cm behind the grating. unfortunately, she has lost the card that gives the specifications of the grating. fortunately, she has a known compound that she can use to calibrate the grating. she heats the known compound, which emits light at a wavelength of 501 nm, and observes a spectral line 9.95 cm from the center of the diffraction pattern. part a:

what is the wavelength emitted by compound a that have spectral line detected at position 8.55 cm?

part b:

what is the wavelength emitted by compound b that have spectral line detected at position and 12.15 cm?