Not a stupid question. The only years that contain any silver are 1942-1945. They are about 35% silver.
Not all of the 1942 ones are silver. The ones with the large P, D, and S mintmarks above Monticello are the silver ones. The ones from 1942 without a mintmark or have a D to the right of Monticello have the standard composition. All of the 1943-1945 "nickels" are silver.