Hi I'm a gm and had a problem last week.
One of my players had the meta magic feat Empower and used it on magic missile.
He argued he would get more missiles instead of 50% more damage on target hit.
I ruled against it, but promised to look into it
He is level 7 and would get 4 missiles normally and instead of 50% more damage he would get an extra 2 missiles for a total of 6 missiles.
I don't really know if it would be game breaking, I'm not good at the math part of pathfinder.
Can you help me?
Your player is wrong. Empower only affects variable numbers which are represented by the die. The number of missiles created by the spell based on caster level is not variable.
The correct way to apply empower spell is to take the damage, in this case its (4(1d4+1))*1.5.
This is further clarified in its interaction with maximize spell