Question

( begin{aligned} frac{1}{lambda} &=Rleft(frac{1}{(pi)^{2}}-frac{1}{left(n_{i}right)^{2}}right) & R=1.097 times 10^{7} mathrm{m}^{-1} & n_{f}=2 & 0 i=4 frac{1}{2} &=1.097 times 10^{7}left(frac{1}{4}-frac{1}{16}right) frac{1}{lambda} &=1.097 times 10^{7} timesleft(frac{12}{64}right) &=frac{64}{12 times 1097} &=4.861 times 10^{-7} mathrm{m} lambda &=4861 mathrm{A}^{0} end{aligned} )

# 21. The wavelength of the radiation emitted when an electron jumps from 4th shell to 2nd shell, is -

Solution