The Bohr radius of the fifth electron of phosphorous alom $\left(a\to mic\nu mber=15\right)$ acting as a dopant in sillcon $\left(relativedie\le ctriccons\tan t=12\right)$ is …….. Å

Answer: A::CSolution: The fifth velence electron of phosphorous is in its third shell , I, e, $n=3$ for phosphorous , $Z=15$ . The Bohr 's radius for nth orbit
$=\frac{9n^2}{Z}{e}_T)\eta =\frac{3^2}{15}\times 12\times 0.529\mathring{A}=3.81\mathring{A}$