text: Willis Lamb made use of this effect when he measured his namesake shift observing a transition from the 2p to the 1s state.
full_question: Willis Lamb made use of this effect when he measured his namesake shift observing a transition from the 2p to the 1s state. An energy within this effect is proportional to the product of the Bohr magneton, the Lande g-factor, and a component of angular momentum. This effect occurs in weaker fields than the similar Paschen-Back Effect, and it is analogous to the Stark Effect, which instead occurs in electric fields. For 10 points, name this splitting of spectral lines in the presence of a magnetic field.
first_sentence: Willis Lamb made use of this effect when he measured his namesake shift observing a transition from the 2p to the 1s state.