For an atom of an ion having single electron, the wavelengths observed are `lambda_(1)=2 units and lambda_(3)=3 units`. The value of missing wavelength `lambda_(2)` is:

Answer

6

Explanation

As is clear form fig.
`E_(1)=E_(2)+E_(3)`
`(hc)/(lambda_(1))=(hc)/(lambda_(2))+(hc)/(lambda_(3))`
`:. 1/(lambda_(1))=1/(lambda_(2))-1/(lambda_(3))=1/2-1/3=1/6 :. lambda_(2)=6 units`