What is difference between good and bad conductors?

Answer 1

Good Conductors, such as silver, copper or aluminium, allow electric current to flow along them, while bad conductors (also termed "good insulators!) such as glass or mica or air impede or prevent electric current flow.

Physically a good conductor is a material containing movable negative electric charges which are electrons or ositive electric charges termed holes. or in the form of ions, such as in the electrolyte of a battery. A proper design of a good electrical conductor takes into account the temperature that the conductor is able to endure without damage, as well as the quantity of current or electrical conductivity.Most familiar and affordable conductors are metallic because metals are elements or substances having one, two or three electrons in their valence shells and their atoms are arranged in a pattern of regular lattice structure called metallic bonding. The valence electrons are therefore free to move around the lattice of positively charged ions as a "sea of electrons".

A bad conductor or good insulator is composed of a material which lacks mobile charges. Hence it resists flow of electric current because its internal electrical charges do not flow freely. Rgat is because its "valence" band containing the highest energy electrons is full, and so a large energy gap separates this band from the next band above it. Such good insulators are thereby made use of in electrical and electronic circuitry specifically to separate electrical conductors without allowing current to pass through themselves.

But good insulators are also made use of as the dielectric of a capacitor that is capacitor consists of two good conductors called its plates separated by a non-conductive region comprising a bad conductor or insulator. Capacitors are extremely commonly used in electronic circuitry such as radio or television receivers. The bad conductor area of a capacitor is known as its dielectricwhich may be air or some material like mica. glass or ceramic. Above a particular electric field, known as the dielectric strength Eds, the dielectric in a capacitor becomes conductive. The voltage at which this occurs is called the capacitors' breakdown voltage that is basically the voltage above which the bad conductor can no longer stop direct current passing through it.