If the binding energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the first excited state of Li++ is 
(a) 122.4 eV        (b) 30.6 eV
(c) 13.6 eV          (d) 3.4 eV

(b) En=13.6n2×Z2

For first excited state n = 2 and for Li++, z =3E=13.64×9=30.6 eV

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