Bohr proposed his atomic model based on Planck's quantum theory and derived following relation for one electron system in `C.G.S` units :
For H-atom ` : r_n =n_2 xx r_2 , E_n = E_1 xx Z^2 , u_n = u_1 /n` ,
`r_1 = 0.529 overset(@)(A) , u_1 = 2. 19 xx 10^8 cm //sec` . , `E_1 =- 13. 6 eV`.
For ` 1` elecron systems . ther than (H) .
` r_n = ( n^2 xx r_(1H))/X , E_n = (E_(1H)xx Z^2)/(n^(2)) , u_n = (u_(1H)xxZ)/n`
Later on de-Broglie propsed the dual nature of elecrron and put forwared his wave concept . The wavelnght of electron in an orbit was given by ` lambda // mu`.
The wavelnght 9 in m^(-1)) of moving electron in 3rd orbit of H-atom is :

Options

A. ` 1. 0 xx 10 ^(-9)`
B. ` 2. 0 xx 10^(-7)`
C. ` 1. 0 xx 10^(-7)`
D. ` 1. 0 xx 10^(-8)`

Answer

A

Explanation

` lambda = h/( mu_3) = (6.626 xx 10^(-34) xx 3)/(9.108 xx 10^(-31) xx u_(1))`
`= (6. 626 xx 10^(34) xx 3)/( 9. 108 xx 10^(-31) xx 2. 19 x 10^6)`
` 9. 96 xx 10^(-10) m`.