If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength λ. When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be
$\dfrac{20}{13}\lambda$
$\dfrac{16}{25}\lambda$
$\dfrac{9}{16}\lambda$
$\dfrac{20}{7}\lambda$
Explanation:
$\dfrac{1}{\lambda} = Re\left(\dfrac{1}{2^2}– \dfrac{1}{3^2}\right)$
$\dfrac{1}{\lambda^{}} = Re\left(\dfrac{1}{3^2}– \dfrac{1}{4^2}\right)$
Dividing $\lambda^{} = \dfrac{20}{7}\lambda$