@WheeledGoat, majorwoo, AristoND: Thank You..
@WheeledGoat: Yes, it has a solid back. I have made two holes in the back side for passing the wires of Filter & light. I've planned to enlarge those holes before finishing the hood!!
@majorwoo: Even I'm worried about the same..!! But, the carpenter said that it was a waterproof plywood, which is safe from damages due to water.. Let's see..
@AristoND: I'am using a Havell's 14W T5 light on a Bajaj e-lux 14W T5 fixture.