An electron joins a helium nucleus to form `He^(+)`. Find the wavelength of the photon emitted in this process (in `nm`) if the electron is assumed to have no kinetic energy when it combines with nucleus. Assume Bhor's nodel to be applicable.

Answer

`22.8 nm`

Explanation

Assuming Bohr's model to be apllicable to the He atom too,
Energy of electron `=-13.6xx4 eV=-54.4 eV` initial energy of electron `=0`
Energy of photon emitted `=544 eV`
`lambda=(hc)/(DeltaE)=22.8 mm`