[Physics Class Notes] on Electricity in Physics Pdf for Exam

Electricity is said to be the presence and flow of electric charge. By using electricity we can transfer energy in ways to another that allow us to do simple chores. Electricity is best-known in the form of the flow of electrons through conductors such as copper wires.

The word “electricity” is sometimes used to mean the energy which is electrical. They are not the same thing:  we can say that electricity is a transmission medium for electrical energy that is for example like seawater is a transmission medium for wave energy. 

Here, we are going to discover more information on electricity. 

History of Electricity 

Any knowledge of electricity did not exist long ago. The people were aware of shocks that were caused by electric fish. Ancient Egyptians had texts dating from 2750 BCE which referred to these fishes as the “Thunderer of the Nile”, and they described them as the “protectors” of all other fish. 

Electricity in Physics

Electricity is all around us- that is the powering technology like our cell phones, computers, lights, soldering irons, and air conditioners. Electricity is said to be a natural phenomenon that occurs throughout nature and it also takes many different forms. Even when we try to escape electricity, it’s still at work throughout nature from the lightning in a thunderstorm to basically the synapses inside our body. 

Current Electricity

Current electricity is the stuff that powers our electronic gadgets operate on. The flow of electricity occurs from a power source through wires and then lights up LEDs, spinning motors and powering our communication devices.

The term electricity is briefly defined as the flow of electric charge. But there’s so much behind that simple statement which we need to understand.  We can ask where do the charges come from? And how do we move them?  So to begin to explain what electricity is we need to zoom in what is beyond the matter and molecules and atoms that make up everything we interact with in life.

Quantification of Electricity

As in the beginning, we have mentioned that electricity is said to be the flow of electric charge. The charge is said to be a property of matter- or we can also say that it’s just like mass and volume or density. It is said to be measurable.  We can say that just as we can quantify how much mass something has so we can also measure how much charge it has. The key concept which we are discussing with charge is that it can come in two types: that is the positive (+) or the negative (-).

In order to move the charge, we need a carrier of charge and that’s where our knowledge of atomic particles, specifically the knowledge of the electrons and protons come in handy. The electrons always carry a charge that is negative, while the protons are always positively charged. The neutrons which are true to their name are neutral so they have no charge.

We can say that both electrons and protons carry the same amount of charge that is just a different type.

The electrons and protons are important because they provide us with the means to exert a force on them which is the electrostatic force.

Conductors and Insulators

An item which usually allows electricity to move through it is known as a conductor. The wires which are made up of copper and other metal items are good conductors, that are generally allowing electricity to move through them and transmit electrical energy. Plastic is said to be a bad conductor, also known as an insulator and does not allow much electricity to move through it so it will stop the transmission of electrical energy.

There are some elemental types of atoms which are better than others at releasing their electrons. To get the best possible electron flow we want to use atoms which don’t hold very tight also to their electrons which lie in the valence shell. The conductivity of the elements generally measures how tightly bound an electron is to an atom.

The elements with high conductivity and which have very mobile electrons are known as conductors. These are the types of materials which we want to use to make wires and other components which aid in the flow of the electrons. Metals like copper, silver, and gold are usually our top choices for good conductors.

The elements which generally have low conductivity are known as insulators. Insulators usually are said to serve a very important purpose: that is they prevent the flow of electrons. Popular insulators include rubber, glass, air, plastic.