Given, ΔE=R¯HZ21n12−1n22RH (Rydberg constant) for H-atom is x m-1. Corresponding value for this constant for He+ ion is

v¯=R¯HZ21n12−1n22R¯H=2π2me4k2ch3=x m−1                      for H-atomR¯Z=2π2me4k2ch3Z2For a species of atomic number Z (with one electron only)R¯ZR¯H=Z2∴ R¯Z=(2)2R¯H=4×m−1=4×100cm−1=0.04×cm−1