Final answer:
The emission line observed at a shorter wavelength in the hydrogen atom depends on the transition between energy levels. The transition from n = 5 to n = 1 has a shorter wavelength than the transition from n = 4 to n = 2.
Step-by-step explanation:
In the hydrogen atom, the emission line observed at a shorter wavelength depends on the transition between energy levels. Using the Balmer series, we can determine the wavelengths of the transitions. The Balmer series corresponds to transitions from higher-energy orbits (n > 2) to the second orbit (n = 2). The transition from n = 5 to n = 1 has a shorter wavelength than the transition from n = 4 to n = 2, making it the emission line observed at the shorter wavelength.