Answer:
[tex]\mathbf{\Delta E = 2.042 \times 10^{-19} \ J}[/tex]
Explanation:
Using the Rydberg expression to calculate the change in energy of a photon emitted, we have :
[tex]\Delta E = R ( \dfrac{1}{n_f^2}-\dfrac{1}{n_i^2})[/tex]
where;
R = Rydberg constant = [tex]2.178 \times 10 {-18} \ J[/tex]
[tex]n_f[/tex] = 1 and [tex]n_i[/tex] = 4
replacing our values into equation, we get:
[tex]\Delta E = 2.178 \times 10^{-19} (\dfrac{1}{1^2}-\dfrac{1}{4^2})[/tex]
[tex]\Delta E = 2.178 \times 10^{-19} (\dfrac{1}{1}-\dfrac{1}{16})[/tex]
[tex]\Delta E = 2.178 \times 10^{-19} (\dfrac{15}{16})[/tex]
[tex]\mathbf{\Delta E = 2.042 \times 10^{-19} \ J}[/tex]