The transition from the state n = 5 to n = 1 in a hydrogen atom results in UV radiation. Infrared radiation will be obtained in the transition
2→1
3→2
4→3
6→2
The transition 4→3 emits the wave of frequency which falls in the range of infrared radiation.
The transition from the state n = 4 to n = 3 in a hydrogen-like atom results in ultra violet radiation. Infrared radiation will be obtained in the transition. (IIT-JEE-2001)