[Ankesh]

What will be the product and how when Cyclohexene reacts with Br₂ in presence of heat and UV light?

[Yasimara]

The UV would produce two bromine radicals, one of which would (non-selectively) remove a hydrogen from the cyclohexane to form an HBr molecule, and a reactive carbon radical. The carbon radical would react with another bromine radical to produce a cyclohexane ring with one of the hydrogens replaced with a bromine. This reaction can continue to produce a further brominated ring depending on temperature, concentration, etc.

[Schrödinger]

The UV would produce two bromine radicals, one of which would (non-selectively) remove a hydrogen from the cyclohexane to form an HBr molecule, and a reactive carbon radical. The carbon radical would react with another bromine radical to produce a cyclohexane ring with one of the hydrogens replaced with a bromine. This reaction can continue to produce a further brominated ring depending on temperature, concentration, etc.

The OP was referring to cyclohexene, not cyclohexane. But in general, what you said is true.
In the case of cyclohexene, carbon - 3 will be attacked because that particular free radical intermediate is more stable :



than the other ones that are possible