Question

The ionisation energy of hydrogen atom is 13.6 ev. The the second inosation energy of He
1) 13.6ev
2) 27.2 ev
3) 40.8 ev
4) 54.4 ev
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Answer 1

Answer:

4) 54.4

Explanation:

E = (13.6xZ^2) / n^2 ev

where, n = number of orbit = 1  

Z = atomic number = 2 (He)

E = (13.6x2^2) / 1^2  

E = (13.6x4) = 54.4 ev

hope this helps you....!!