Q.

The transition from the state n=4 to n=3 in a hydrogen-like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition.            [2001]

1 2 → 1  
2 3 → 2  
3 4 → 2  
4 5 → 4  

Ans.

(4)

For state transition, 2 to 1, 3 to 2 and 4 to 2 we get energy that n=4 to n=3,

Infrared radiation has less energy and greater than ultraviolet radiation.

Infrared radiation will be obtained in the transition 5 to 4.