Consider that an electron is revolving in an excited state of Hydrogen atom with velocity
\[
\sqrt{25.6}\times10^5 \ \text{ms}^{-1}.
\]
The radius of the orbit is \(x\times10^{-9}\) m. The value of \(x\) is :
[Take mass of electron \(=9\times10^{-31}\) kg, charge of electron \(=-1.6\times10^{-19}\) C and
\[
\frac{1}{4\pi\varepsilon_0}=9\times10^9 \ \text{Nm}^2\text{C}^{-2}
\]
