Question

which rays are useful for us​

Answer 1

all raysuseful except infrared UV rays

Answer 2

hey mate .☺☺❣

here is ur answer..

X-rays are types of electromagnetic radiation probably most well-known for their ability to see through a person's skin and reveal images of the bones beneath it. Advances in technology have led to more powerful and focused X-ray beams as well as ever greater applications of these light waves, from imaging teensy biological cells and structural components of materials like cement to killing cancer cells.  

i hope its help u ♥️♥️⭐