Answer:
![4.86*10^(-7)\ \text{m}](https://img.qammunity.org/2022/formulas/chemistry/college/wb12g0f9cpgmawt4sp40xuhokels8wcd71.png)
Step-by-step explanation:
R = Rydberg constant =
![1.09677583* 10^7\ \text{m}^(-1)](https://img.qammunity.org/2022/formulas/chemistry/college/fylbeuqrb8rynsawb1ud3ah48g3ku3t6u3.png)
= Principal quantum number of an energy level = 2
= Principal quantum number of an energy level for the atomic electron transition = 4
Wavelength is given by the Rydberg formula
![\lambda^(-1)=R\left((1)/(n_1^2)-(1)/(n_2^2)\right)\\\Rightarrow \lambda^(-1)=1.09677583* 10^7\left((1)/(2^2)-(1)/(4^2)\right)\\\Rightarrow \lambda=\left(1.09677583* 10^7\left((1)/(2^2)-(1)/(4^2)\right)\right)^(-1)\\\Rightarrow \lambda=4.86*10^(-7)\ \text{m}](https://img.qammunity.org/2022/formulas/chemistry/college/fjr7aws5q2519oknmqtrf8iv7ugiwp8tep.png)
The wavelength of the light emitted is
.