To solve this, we must first find the value of the
wavelength using the formula:
1/ʎ = R [1/(nfinal)^2 – 1/(ninitial)^2]
where ʎ is wavelength and R is Rydberg’s constant = 10,973,731.6
m-1
1/ʎ = 10,973,731.6 m-1 [1/2^2 – 1/4^2]
1/ʎ = 2,057,574.675 m-1
ʎ = 4.86 x 10^-7 m
Then compute for energy using the equation:
E = hc / ʎ
where h is Plancks constant = 6.63 x 10^-34 J s, c is
speed of light = 3 x 10^8 m/s
E = (6.63 x 10^-34 J s) (3 x 10^8 m/s) / 4.86 x 10^-7 m
E = 4.09 x 10^-19 J
