Energy levels: plus or minus?
The Energy Level Diagram in the NYS Physics Regents Reference Tables lists the ground state energy for Hydrogen as –13.60 eV and the one of infinity as 0.00 eV. Other tables I have seen reverse these values. I would like to know the reasoning in each case! Reply The values –13.6 eV for the ground state is appropriate, though formally of course potential energy is defined within an arbitrary constant, added to ALL values. So if you were to add 13.6 eV everywhere, the ground state energy would be 0, but ay infinity the energy is +13.6 eV, with plus sign. The situation is similar with gravitational energy–say, planets around the Sun, or satellites around Earth: all bound orbits have negative energy. If you add energy to (say) a satellite), it climbs to a higher orbit with a less negative (total) energy. If the total energy is zero, it is just escaping on a parabolic orbits, and any spacecraft with positive total energy is unbound. The gravitational case is discussed in http://www.phy6.or
