Its 10.2 eV or 2.55 eV.
R= .529 *(n^2/Z )
n = no. Of orbit
Z = atomic no.
Given R1/R2 = 4:1
n1^2/n2^2 = 4:1
n1/n2 = 2:1
Among 1st 4 orbits
n1 = 4 or 2
n2 = 2 or 1
If n1 = 4 then n2 =2
Or n1= 2 then n2 = 1
Use energy equation then
E = -13.6 *(Z^2 / n^2 )
For case 1 ∆E = 2.55 eV
For case 2 ∆E = 10.2 ev
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