Question

How did hulk become green? Which type of radiation was he exposed to?​

Answer 1

$\huge\fbox\red{A}\fbox\pink{n}\fbox\purple{S} \fbox\green{w}\fbox\blue{E}\fbox\orange{r}$

❥Throughout that time we've also been battling to master what originally turned him from a mild mannered scientist into a super-powered monster: gamma radiation. ... Dr Bruce Banner is transmuted by exposure to gamma rays in Hulk #1 in May 1962.

Answer 2

Due to some experiment ultraviolet radiation exposed and makes Bruce green which later know as hulk.