at the low temperatures found in some interstellar molecular clouds (around 100 k), molecular oxygen emission is strongest at a wavelength is 0.2521...

at the low temperatures found in some interstellar molecular clouds (around 100 k), molecular oxygen emission is strongest at a wavelength is 0.2521 cm. determine the speed (in/kms) of a low temperature molecular cload containing molecular oxygen if its strongest emission is at a wavelength of 0.1840 cm. this cloud is moving toward us, so your answer should be negative.