A He⁺ ion is initially in its ground state. What minimum energy must be supplied to excite its electron to the second Bohr orbit?
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Question

A He⁺ ion is initially in its ground state. What minimum energy must be supplied to excite its electron to the second Bohr orbit?

G1 Physics · Accepted Answer

For He⁺, Z = 2. Energy levels are Eₙ = −13.6Z² ÷ n². Ground state: E₁ = −13.6×4 = −54.4 eV. Second orbit: E₂ = −54.4 ÷ 4 = −13.6 eV. Required excitation energy: ΔE = −13.6−(−54.4) = 40.8 eV. Correct option: C.