1. a sphere (radius r, total charge q uniformly distributed throughout the volume) is spinning at angular velocity w about its center, which is at the origin. what is the volume current density j (r,0, d) at any point (r, θ, φ) in the sphere? (don't forget direction too! )2. a very thin plastic ring (radius r) has a constant linear charge density, and total charge q. the ring spins at angular velocity w about its center, which is the origin. what is the current i, in terms of given quantities? what is the volume current density j in cylindrical coordinates? (this may be a little tricky, since the ring is very thin there will be some functions. hint: write down a formula for r, θ first. and, remember that j should be a vector! )