Which of the following series of lines are the only lines in hydrogen spectrum which appear in the visible region.

Options

A. Lyman series
B. Balmer series
C. Paschen series
D. Bracket series

Answer

B

Explanation

`(1)/(lamda)= R ((1)/(n_(1)^(2))- (1)/(n_(2)^(2)))`
for Balmer series `n_(1) = 2`,
Let `n_(2) rarr oo` (for shortest wavelength)
`(1)/(lamda)= 1.097 xx 10^(7) ((1)/(4)) rArr lamda= (4 xx 10^(-7))/(1.097) ~~400nm`