Calculate (a) the wavelength and (b) the frequencey of the `Hbeta`
line of the Balmer series for hydrogen.

Explanation

a. `H_(beta)` line of Balmer series corrresponds to the transition from `n = 4` to `n = 2`level . The corrresponds wavelength for `H_(beta)` line is ` (1)/(lambda) = (1.097 xx 10^(7)) [(1)/(2^(2)) - (1)/(4^(2))]`
`= 0.2056 xx 10^(7) m`
`lambda = 4.9 xx 10^(-7)) m` ltrbgt b. `f = (c )/(lambda) = (3.0 xx 10^(8))/(4.9 xx 10^(-7))`
`= 6.12 xx 10^(14) Hz`