Magnetic fields are always associated with: 1). charge motion2). metals3). electrolytes 4). static charges

1. Charge motion

Explanation:

Coulomb's Law explains that electrically charged bodies exert forces on one another. When the charged bodies are in a state of rest, the forces are electric. Electric fields act as sources of these forces. However, when the charged bodies are in motion, there are additional forces to the electric forces, these new forces are magnetic and are caused by magnetic fields that are created by the charges that are in motion.

For that, magnetic fields are always associated with charge motion

b hope this

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.