Energy of an electron in nth orbit of hydrogen atom is $\left(k=\frac{1}{4 \pi \varepsilon_0}\right)$

$-\frac{2 \pi^2 k^2 m e^4}{n^2 h^2}$ $-\frac{4 \pi^2 m k e^2}{n^2 h^2}$ $-\frac{n^2 h^2}{2 \pi k m e^4}$ $-\frac{n^2 h^2}{4 \pi^2 k m e^2}$

$-\frac{2 \pi^2 k^2 m e^4}{n^2 h^2}$

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