Answer:
3.96193 × 10^-7m
Explanation:
I have added the formula used as an attachment.
Now, lambda is the wavelength of the emitted photon
R is the Rydberg's constant
n(final) is the final energy level which in your case is 2
n(initial) is the initial energy level which in your case is 7.
Thus, we input these values into the equation.
1/lambda = 1.0974 × 10^7 ( 1/2^2 - 1/7^2)
1/lambda = 1.0974 × 10^7 × 0.23
= 2,524,020m^-1
Hence lamba = 1/2524020 =
3.96193 × 10^-7m
