靜電是正電荷還是負電荷

靜電是正電荷還是負電荷?
Both +ve and -ve charges exist.In the actual fact, charges in static electricity is no different than those in current eelctricity except that the former are not mobile.

為甚麼靜電可以吸到東西?
Generally, by induction of opposite charges on an object. The attractive force arises because of attraction between opposite charges.

靜電與磁場有關係嗎?

No. Static charges produce electric field, which is different from magnetic field.