Question

Energy of an electron is given by $E=-2.178\times {10}^{-18}J\left(\frac{Z^2}{n^2}\right)$ Wavelength of light required to excite an electron in an hydrogen atom from level n=1 to n=2 will be:-`
$(h=6.62\times {10}^{-34}Jsandc=3.0\times {10}^8{ms}^{-1})$

• A. $1.214\times {10}^{-7}m$
• B. $2.816\times {10}^{-7}m$
• C. $6.500\times {10}^{-7}m$
• D. $8.500\times {10}^{-7}m$

Answer 1

The correct option is A $1.214\times {10}^{-7}m$

$\begin{array}{c}\frac{1}{\lambda }=R_H{Z}^2\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)\\ Z=1\\ n_1=1\\ n_2=2\\ \lambda =1.24\times {10}^{-7}m\end{array}$