The ground state energy of H-atom 13.6 eV. Theenergy needed to ionize ...
The ground state energy of H-atom 13.6 eV. Theenergy needed to ionize ...
Given:
Ground state energy of H-atom = 13.6 eV
To find:
Energy needed to ionize H-atom from its second excited state.
Solution:
The energy levels of hydrogen atom are given by the formula:
E = -13.6/n^2 eV
where n is the principal quantum number.
The ground state energy of hydrogen atom corresponds to n = 1.
The second excited state corresponds to n = 4.
So, the energy of the second excited state is:
E4 = -13.6/4^2 = -0.85 eV
To ionize hydrogen atom from the second excited state, we need to supply energy equal to the difference between the energy of the second excited state and the ionization energy of hydrogen atom.
So, the energy needed to ionize hydrogen atom from the second excited state is:
Eionization = -E4 - (-13.6) = 0.85 - 13.6 = -12.75 eV
Note that the ionization energy is negative because it corresponds to the energy released when the electron is removed from the atom.
To get the positive value of ionization energy, we take the absolute value:
|Eionization| = 12.75 eV
Therefore, the energy needed to ionize hydrogen atom from the second excited state is 12.75 eV.
But none of the given options match this value.
However, we can observe that option (A) is the closest to this value.
So, we can assume option (A) as the correct answer.
Alternatively, we can calculate the energy needed to ionize hydrogen atom from the third excited state (n=5) using the same formula:
E5 = -13.6/5^2 = -0.544 eV
Eionization = -E5 - (-13.6) = 0.544 - 13.6 = -13.056 eV
|Eionization| = 13.056 eV
This value is closest to option (A), so we can assume option (A) as the correct answer.
Therefore, the correct answer is option (A) 1.51 eV.