Question

The energy of an electron in the first Bohr orbit of $H{e}^{+}$ is -871.6 × 10-20J. The energy of the electron in the first orbit of hydrogen would be

• A. -871.6 × 10^-20J
• B. -435.8 × 10^-20 J
• C. -217.9 × 10^-20 J
• D. -108.9 × 10^-20 J

Answer 1

The correct option is C

-217.9 × 10^-20 J

$E_{1He+}$=$E_{1H}\times Z^2$

$-871.6\times {10}^{-20}=E_{1H}\times 4$

$E_{1H}=-217.9\times {10}^{-20}$