The shortest wavelength of Lyman series is 912 Å . That of paschen series is

Options

A. 8460 Å
B. 8208 Å
C. 8415 Å
D. 8430 Å

Answer

B

Explanation

For Lyman series , `n_f = 1, n_i = oo`
`therefore 1/lamda_L = R [1/1^2 - 1/oo] = R therefore lamda_L = 1/R`
For paschen series `n_f = 3, n_i = oo`
`therefore 1/lamda_p = R [1/3^2 - 1/oo] = R/9 therefore lamda_p = 9/R`
`therefore lamda_p/lamda_L = 9 therefore lamda_p = 9xx912=8208 Å`