This question is about electrostatic charge and the conditions required for electrical current.
An inflated rubber balloon is rubbed against a woolen jumper, acquiring a net negative charge. When the balloon is brought near a vertical, uncharged wooden wall, it is attracted to and clings to the wall. Explain, in terms of electrostatic forces and charge distribution, why the uncharged wall attracts the negatively charged balloon.
State the two essential requirements that must be met for a steady, continuous electric current to be maintained in an electrical network.
A high-intensity LED indicator in an optical communication transceiver operates with a steady current of 48 mA48\text{ mA}48 mA. Calculate the total charge, in coulombs, that passes through the LED during an operational cycle of 2.5 hours2.5\text{ hours}2.5 hours.