Answer:
Utra violet waves
Step-by-step explanation:
Frequency of a wave determines it's color. Red light has frequency 4×10{14} Hz and the violet light has 8×10{14} Hz. So, if our vision somehow began to increase so that you could see higher and higher frequencies beyond visible light we will first start seeing utraviolet frequencies, it is the next frequency after the violet light in visible rays. However, humans can not perceive it.