Calculate the wavelength of the two spectral lines with the longest wavelengths (called the first two lines ) in the visible region of the atomic spectrum of hydrogen,
Strategy: Use Balmer's formula, Eq. to calculate the wavelength of visible lines in the atmoic emission spectrum of hydrogen. To calculate the wavelengths of the first two lines, used the two smallest allowed integers, `n = 3`and `n =4`, in the Balmer formula because `lambda` is inversely related to `n`.