[Physics Class Notes] on Electricity Pdf for Exam

What is Electricity?

Electricity is defined as the set of physical phenomena associated with the motion and presence of matter with a property of electric charge. As described by Maxwell’s equations, electricity is related to magnetism, both being part of electromagnetism and phenomenon. Different common phenomena are related to electricity, including lightning, electric heating, static electricity, electric discharges, and many other ones.

The presence of an electric charge, being positive or negative, produces an electric field. The movement of electric charges is nothing but an electric current and produces a magnetic field.

When a charge is placed in a non-zero electric field location, a force will act on it. Coulomb’s law gives this force magnitude. Therefore, if that charge were to move, the electric field would be working on the electric charge. Moreover, we can speak about the electric potential at a point in certain space, which in turn equal to the work accomplished by an external agent in carrying a positive charge unit from an arbitrarily chosen reference point without any acceleration and is typically measured in volts.

Best Electricity Conductors

Metals like gold, copper, silver, aluminium, steel, and brass are a few most common and best electricity conductors. All these elements possess individual properties that help them to come in use for various purposes.

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Gold

Gold is the best conductor of electricity. Gold does not tarnish quickly when we expose it to air, unlike other metals. Besides, other metals like copper or steel corrode when they exposed to oxygen for a long time. Furthermore, it also stays conductive for a more extended period.

Gold is quite expensive, and we use it in only specific materials like circuit board parts or small electrical connectors. Besides, for some substances, gold plating is done to use as an electric conductor. Also, this plating helps in reducing manufacturing costs.

Copper and Silver

They are the most and best frequent conductor of electricity. Silver has a big count of movable atoms that makes it an excellent conductor. To put differently, a good conductor possesses a considerable amount of free electrons in return, allowing smooth electron movement producing more conductivity.

Nevertheless, silver is also quite costly, just like gold, when compared to other metals. That is why we utilize it mostly in special equipment like circuit boards or satellites. Besides, copper is not a good conductor as silver. However, it is cheaper to make it a common component in household items.

Many wires that we find in our homes are copper plated. Further, we also use copper wires in wrapping electromagnet cores. Indeed, it is easy to solder it and wrap it into wires. Thus, we frequently use it when we need a vast amount of conductive material.

Steel and Brass Alloys

Steel is an alloy of iron. It can fall into the list of best electricity conductors definitely. This is inflexible metal and corrodes greatly when exposed to air. We do not use them in small products or machines because of casting difficulties. Therefore, we can use steel to encase other conductors or for a large structure.

Brass also is an alloy and quite a tensile metal. The easy moulding and bending of these metals make it perfect to use in small machines. However, it does not corrode easily compared to steel and also more conductive. These rates are not that high and worthwhile compared to steel alloy, which is useful when bought first.

Aluminium

Aluminium is also the quite best conductor of electricity. Furthermore, it is so conducive when compared to copper. Also, it does not cost too much as copper making it quite reasonable in comparison. We use it in wiring and household items.

However, it is not that common, and sometimes we can avoid it because of its structural drawbacks. Mainly, it has a use for high-voltage transmission lines such as phone cables overhead and more.

Sources of Electricity

A few of the primary sources of electricity are given below.

  1. Electricity by Rubbing

The primary observations on electrical phenomena were made in ancient Greece. This has happened when the philosopher, named Thales of Miletus (640-546 BC), found when amber bars are rubbed against tanned skin; they produce attractive characteristics that previously did not possess.

This is similar to rubbing a plastic bar with a cloth now. Bringing it closer to small pieces of paper attracts them, as characteristic of electrified bodies.

  1. Electricity Generated by Pressure

This is also one of the right sources of electricity. The pressure exerted by underground water flows is used as alternative energy in large ships to the main system. Electricity in dams is generated by releasing a controlled flow of high-pressure water via a forced conduit.

The water drives turbines that move the generators and, thereby producing an electric current. This low-voltage of high current passes then through a voltage booster, which transforms it into electricity.

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