If $E_p$ and $E_k$ represents the potential and kinetic energy respectively of an orbital electron, then according to Bohr's theory.

$E_k=-\frac{E_p}{2}$

The correct answer is Option (1) → $E_k=-\frac{E_p}{2}$

for all the electrons in a given orbit -

Energy, $E=-K.E.=\frac{v}{2}$

where, $v$ = Potential energy

$∴K.E.=-\frac{v}{2}$

$⇒E_k=-\frac{E_p}{2}$