What is the Major product in free radical halogenation of Alkanes. (Between 3°,2°,1°)
It depends on what halogen you use. 

Chlorine has a reactivity ratio for $1^o$:$2^o$:$3^o$= 1 : 3.5 : 5. 

To calculate the relative yield at that position, multiply the number of Hydrogens at that position to the reactivity at that position. This will give you a comparison of the yield at particular positions. 

But in the case of bromine, the reactivity order is 1 : 250 : 6300. Therefore, without any further thinking, the bromine radical will always attack at the tertiary position if available. 

In general, reactivity towards tertiary carbon increases down the group as in the case of halogens.