A 14.8-g piece of Styrofoam carries a net charge of -0.742 µC and is suspended in equilibrium above the center of a large, horizontal sheet of plastic that has a uniform charge density on its surface. What is the charge per unit area on the plastic sheet?

Question

anonymous · Answer

Use the expression for the field of a sheet of charge
then F=qE =mg

anonymous · Answer

Great, just got it together so $$\sigma = (m*g*2*\epsilon0)/q$$ thanks

anonymous · Answer

looks good:)