A photon on a hydrogen atom excited an electron from n = 1 to make a transition to n=3. What is the wavelength (in run) pertaining to this transition and was the transition emitting or absorbing in nature?

1 Answer
Dec 8, 2015

=>lambda=102.6nm

Energy is absorbed.

Explanation:

In order to solve this question we will use the Bohr Model.

The change in energy according to Bohr can be calculated by:

DeltaE=-2.178xx10^(-18)Z^(2)J(1/(n_("final")^2)-1/(n_("initial")^2))

Here, the initial level is n_("initial")=1 and the final level is n_("final")=3. Since this is hydrogen, then Z=1.

Thus, DeltaE=-2.178xx10^(-18)(1)^(2)J(1/(9)-1/(1))=1.936xx10^(-18)J

This energy can also be given as DeltaE=hnu=hc/(lambda)

=>lambda=hc/(DeltaE)=(6.626xx10^(-34)xx2.998xx10^8)/(1.936xx10^(-18))=1.026xx10^(-7)m

=>lambda=102.6nm

Since the electron is moving from a lower energy level to a higher energy level, the energy is absorbed.

Moreover, we can say that the energy is absorbed because the sign of DeltaE is positive (DeltaE>0).