The ratio is 10.5:1. 1050 magicka is 100 spell power and the same goes for stamina and weapon power.
Prior to this last update, light and heavy weapon attacks worked differently and the ratio for those used to be more like 40:1 so stacking spell power / weapon power over magicka or stamina made sense for the LA/HA weaving part of your rotation. But now they work the same way it does for abilities and it's 10.5:1 for everything.
ThePurplePanther wrote: »These things should be in a complete, official, (online) guide. All those details, for instance difference between weapon and spell damage, the fact that the higher a pool, the more damage, the different types of damage, and for ex. what is penetration, and why does it differ from damage, ... etc; and so on.
It is not logical to me, that in order to find the answers, we need to search on unofficial wiki's, ask other players, wild guessing, etc.
The guides that are on the official website of ESO are telling way too little.