What is the energy, momentum, and wavelength of a photon that is emitted by a hydrogen atom making a direct transition from an excited state with n = 10 to the ground state? find the recoil speed of the hydrogen atom in this process.

Acertain half-reaction has a standard reduction potential e_red^0 = -0.94 v. an engineer proposes using this half-reaction at the cathode of a galvanic cell that e must provide at least 1.00 v of electrical power. the cell will operate under standard conditions. a. is there a minimum standard reduction potential that the half-reaction used at the anode of this cell can have? b. is there a maximum standard reduction potential that the half-reaction used at the anode of this cell can have?