Question

Given the value of Rydberg constant is `10^(7)m^(-1)`, the waves number of the lest line of the Balmer series in hydrogen spectrum will be:
A. `0.5xx10^(7)m^(-1)`
B. `0.25xx10^(7)m^(-1)`
C. `2.5xx10^(7)m^(-1)`
D. `0.025xx10^(4)m^(-1)`

Answer 1

Correct Answer - B
Here, `R=10^(7)m^(-1), barv=?`
for last of Balmer series, `n_(1)=2, n_(2)=oo`
`barv=1/lambda=R(1/(n_(1)^(2))-1/(n_(2)^(2)))=10^(7)(1/(2^(2))-1/(oo^(2)))`
`=0.25xx10^(7)m^(-1)`