J.R. S. answered 04/03/20
Ph.D. University Professor with 10+ years Tutoring Experience
Use the formula E = -2.178x10-18 J (1/nf2 - 1/ni2) where nf is final n and ni is initial n
nf = 3
ni = 5
E = -2.178x10-18 J (1/9 - 1//15)
E = -2.178x10-18 (0.1111 - 0.04)
E = -2.178x10-18 (0.0711)
E = -1.549x10-19 J
nf = 2
ni = 5
E = -2.178x10-18 J (1/4 - 1//25)
E = -2.178x10-18 (0.25 - 0.04)
E = -2.178x10-18 (0.21)
E = -4.574x10-19 J
wavelength = λ
E = hc/λ
λ = hc/E = (6.626x10-34 Jsec)(3x108 m) / 4.574x10-19 J
λ = 4.346x10-7 m = 434.6 nm