Q.

During the transition of electron from state A to state C of a Bohr atom, the wavelength of emitted radiation is 2000 A° and it becomes 6000 A° when the electron jumps from state B to state C. Then the wavelength of the radiation emitted during the transition of electrons from state A to state B is         [2025]

1 3000 A°  
2 6000 A°  
3 4000 A°  
4 2000 A°  

Ans.

(1)

For A to C : EA–EC=hc2000 A°          ... (i)

and for B to C : EB–EC=hc6000 A°          ... (ii)

Now for A to B : EA–EB=(EA–EC)–(EB–EC)

hcλAB=hc2000–hc6000

1λAB=13000 A° ⇒ λAB=3000 A°