Chemistry
posted by Lily .
calculate the wavelength of the second line in the Brackett series (nf=4) of the hydrogen emission spectrum. Rh= 2.180e18
any help please? i know its energy levels 4 to 6... but that is all.

1/lambda= R (1/4^21/662) R= Rydberg constant = (1.09678E7 m^1)
A little algebra changes this to
1/lambda= R (3616)/(16*36)
solve for lambda.