In the spectrum of a hypothetical atom, we discover a line with wavelength ... ...

 In the spectrum of a hypothetical atom, we discover a line with wavelength 1.5 x 10–7m, and we discover that the transition is from the ground state. The ground state corresponds to zero energy. What other energy level must exist in the atom? (Use c = 3.0 x 108 m/s and h = 6.63 x 10–34 J s.)
(A) –3.0 x 10–32 J
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in 16. Atomic and Nuclear Physics