Question

A single electron is revolving orbits a round nucleus a stationary (z = 5). The energy required to excite the electron from the third to the fourth Bohr orbit will be:

• A. 4.5 eV
• B. 8.53 eV
• C. 25 eV
• D. 16.53 eV

Answer 1

Answer: (D)

16.53 eV

$\Delta E=E_4-E_3$

$=-\frac{13.6\times Z^2}{16}+\frac{13.6\times Z^2}{9}$

= $-13.6\times 25[\frac{-1}{9}+\frac{1}{16}]=16.5$ eV