[单选题]
In a ruby laser, an eleca+ w r(c /fiye9k0.ldqtrongk/k:7x rp8ig jumps from a higher energy level to a lower one. If the energy difference between the two levels is 1.8 eV,/78pgr ikkg: x what is the wavelength of the emitted photon?
A. $469 \; nm$
B. $649 \; nm$
C. $694 \; nm$
D. $964 \; nm$
Post time 2024-1-22 00:52:27