Positronium is an atom formed by an electron and a positron (anti-electron). It is similar to the hydrogen atom, with the positron replacing the proton. If a positronium atom makes a transition from a state with n = 3 to a state with n = 1, the energy of the photon emitted in this transition is closest to
A. 6.0 eV
B. 6.8 eV
C. 12.2 eV
D. 13.6 eV
E. 24.2 eV
(GR0177 #31)
Solution:
Energy levels of Positronium is half those of Hydrogen (See GR8677 #99)
En(H) = −13.6/n²
En(Ps) = ½ En(H) = −6.8/n²
For transition n = 3 to n = 1
EPs = −6.8 (1/3² − 1/1²) = (−6.8)(−8/9) = 6.04 eV
Answer: A
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