1. In 1896 Pickering found lines from the star Zeta Puppis that had not been observed on Earth. Bohr showed in 1913 that the lines were due to He+. Show that an equation giving these wavelengths is.
2. Calculate the three longest wavelengths and the series limit for the molybdenum atom.
3. An unknown element is used as a target in an x-ray tube. Measurements show that the characteristic spectral lines with the longest wavelengths are 0.155 nm and 0.131 nm. What is the element? (Hint: you will ?nd the answer to Problem 40 to be useful.)