6.1 Basics of Physics & Electronics

Description:

Recapitulating the basics of the Physics and Electronics are essential to get a clear picture of the upcoming blogs.

Physics:

• The term ‘Physics’ comes from the root word ‘Phys’ meaning nature and natural order.

• Physics is the study of physical properties. It involves the study of everything in physical existence from smallest subatomic particles to the entire universe.

• Study of natural forces refers to the study of heat, light, sound, pressure, electricity etc.

Physics can be broadly classified as:

• Mechanics: This focuses on the behavior of object and the forces that act upon them.

• Thermodynamics: Study of heat, temperature and energy.

• Optics: Study of light waves.

• Acoustics: Study of sound waves

• Electro-magnetism: Study of electric and magnetic forces.

ATOM

• The term ATOM comes from the Greek word “ATOMOS” meaning “Indivisible”, but the basic idea that matter is made up of tiny indivisible particles is an old idea that appeared in many ancient cultures such as those of Greece and India.

• Researches from the University of Bonn have just shown how a single atom can be split into its two halves, pulled apart and put back together again. While the word atom literally means indivisible the law of quantum mechanics allows dividing atoms similarly to light rays and reuniting them.

• Atom is the building block of matter. Atoms were created after big bang 13.7 billion years ago. The earliest atoms were primarily hydrogen and helium which are still the most abundant elements in the Universe.

An atom is composed of sub-atomic particles and these cannot be made or destroyed

Proton – Positively charged

Neutron – Uncharged

Electron – Negatively charged

The negative charge of one electron balances the positive charge of one proton. Therefore, an atom has no charge. Atoms are neutral in electric charge because they have same number of protons and electrons. However, if atoms lose or gain electrons, they became charged particles called ions.

Protons: Positively charged subatomic particles located in the nucleus of an atom 

Neutron: Neutrally charged subatomic particles located in the nucleus of an atom 

Electrons: Negatively charged subatomic particles located in the orbitals surrounding the nucleus.

What is Electric Current?

• Electric current (I) is the rate of flow of electrons in a conductor. Electrons which are negatively charged move from one atom to another, and we call that movement as Electric current.

• SI unit of electric current(I) = Ampere(A)

• Ampere is a unit used to quantify the current flowing in a system

• $Ampere \left(A\right) = \frac{1 Coulomb}{1 Second}$

Number of electrons that are able to move governs the ability of a particular substance to conduct electricity (or) in other words Electric current flows more easily in some types of atoms than in others 

Atoms that let current flow easily are called conductors, whereas atoms that don’t let current flow easily are called insulators.

Electrical wires are made of both conductors and insulators. Inside the wire is a conductor, such as copper or aluminum. The conductor provides a channel for the electric current to flow through. Surrounding the conductor is an outer layer of insulator, such as plastic or rubber

Why is this girl’s hair standing straight up?

She is touching a device called Van de Graff generator. The dome on the top has negative electric charge. She became negatively charged because, electrons flowed from Van de Graff generator to her. Whenever electrons are transferred between objects, neutral matter becomes charged. This occurs even with individual atoms.

All of the hairs have become negatively charged, and like charges repel each other. Therefore, hairs are pushing away from each other, causing them to stand on end.

Read the next post: 6.2 What is Voltage?