1. According to Figure 10, how many transitions can an electron in quantum level 3 make in returning to the ground state?
2. Two predominant spectral lines in the hydrogen spectrum, an infrared one and a red one, have frequencies 2.7\times 10^{14} Hz and 4.6\times 10^{14} HZ, respectively. Can you predict a higher- frequency line in the hydrogen spectrum?
1. Three (transitions A, B, and C), as shown in Figure 10.
2. The sum of the frequencies is 2.7\times 10^{14} Hz + 4.6\times 10^{14} HZ = 7.3\times 10^{14} HZ, which happens to be the frequency of a violet line in the hydrogen spectrum. Using Figure 10 as a model, can you see that, if the infrared line is produced by a transition corresponding to path A and the red line corresponds to path B, then the blue line corresponds to path C?