Hello everyone. Today we want to start our study of Physics: electricity and magnetism
The book I'm using is "Essential University Physics" 2nd edition, by Richard Wolfson
Now, you may be asking yourself: "Why should I care about learning electromagnetism?"
To answer your question, I placed a picture here of planet earth
As you can see, the surface of the earth is showered in artificial light, which we know all about
And they are produced using the energy of electricity
Now, since we know these lights are produced using electricity, we also need to know that magnetism too played a role in the matter.
Because the electric generators use magnetism to produce electricity, which we will later learn all about
So that was one example of why electricity and magnetism are important to learn about
Had we not learned about electromagnetism, we would be living in the dark
Well.. Let me give you a few more examples
If we try and look around to find where else electromagnetism is at play,
We find out that the electric force is one of the most fundamental forces of nature
In fact electric forces are a fundamental force governing the behavior of atoms, molecules, galaxies (at their molecular level)
The electric force affects the motion and behaviour of charges, atoms, and molecules
For example, let me plant a positive charge here
An electric field (which we will learn much about later), but just as an example for now,
The positive charge gets repelled by the field and gains an acceleration to the right (due to the electric force produced by the electric field)
Quick note: I expect that you know your Newtonian mechanics before learning about this course
Because if you don't, we won't be able to go on and understand electromagnetism
You must also know your Algebra, Geometry, Trigonometry, some differential and integral calculus,
some vector calculus to understand fields
However don't worry about the vector calculus too much, if you don't understand the mathematics, focus on the physics
So, if we direct the electric field in the direction of the charge, the charge will gain an acceleration to the right (due to the electric force caused by the electric field)
Well, if we look at the motion of the charged particle, we'd notice that the electric forces produced by electric fields play much bigger roles
than forces such as gravity due to the earth's gravitational field
Because if we look at the mass of the earth and compare it with the charged particle
The mass of the earth is much bigger than the particle's
And if you recall Newton's law of universal gravitation,
Where the constant G is very small, in the order of 10 to the power of -7
Let's call m1 the mass of the earth, and m2 as the mass of the particle
Well if we multiply the mass of earth, mass of the particle, and G, the numerator will be relatively tiny
And if we divide this product by r squared - the square of the distance between the centers of the earth and the particle - the force will be negligible
For that reason, we will ignore the gravitational force in this case, and realize that electric forces are more important for charged particles, because:
The electric field interacts with a particular property of this particle, called its "charge"
Which physicists don't currently understand the cause for its existence, or its origins
Much like the existence and origins of mass.
We know intuitively, that when we push an object, it has a certain resistance to change in motion, called its "inertia"
For that reason, we observe that charged particles interact much more strongly with electric fields, than gravitational fields.
Knowing that fact, we can look at some examples to find where electric fields and forces play a role
Consider the electromagnetic technologies present today,
You find that computer microchips, cell phones, large electric motors and generators (which produce these lights, using both electricity and magnetism)
These were some prime example of the fruits of electromagnetism and its impact on modern technology, which we depend on
Turns out, electromagnetism doesn't only play a role in technologies, in nature we find systems
That are important to us as humans.
Such as the human heartbeat, being produced by an electric signal from the brain to the heart muscles
Which Neuroscientists know all about and can measure these phenomena
Some more  examples of electromagnetic influence on natural systems include the structure of a cells.
The nature of cells and their mechanism for functioning is electricity
Which mediates the amount of materials flowing in and out of the cells
Now, let's see what is at the heart of electromagnetism, what are we trying to understand?
Here we have what are called "Maxwell's Equations"
Don't get intimidated by these equations, we will delve deep into them and use many examples in the appropriate time
James Clerk Maxwell did some interesting experiments approximately during the years 1861 - 1868
He came to the realization that the findings of Mr. Faraday, Mr. Gauss, and Mr. Ampere regarding electric fields, magnetic fields, and electric currents,
Were all related. Electricity, magnetism, and electric currents somehow relate to one another
He concluded that there is a phenomenon where under the right circumstances, electric and magnetic fields produce one-another
And oscillate in strength.
He also concluded that light is an electromagnetic wave
If we draw a 3 dimensional x, y ,z coordinate system
We can draw light as an electric field oscillating up and down in the y-axis and a magnetic field oscillating up and down in the z-axis
Where the electric and magnetic fields are always orthogonal (perpendicular, at 90 degrees) with eachother
By solving the wave equation (differential equation), he found out that the speed of an electromagnetic wave is the speed of light
Which was the basis for his conclusion that light was an electromagnetic wave (not a good basis in general, worked this time)
and that speed is c = 3*10^8 meters per second
This was the first unification of seemingly unrelated forces and fields in the history of physics.
This helped scientists make various predictions, based on the findings.
Remember that in science, and especially in physics, we want to be able to predict phenomena
Given certain results from experiments and models produced that help us understand natural phenomena
We will understand these equations later. Take away this, these equations are very important and at the heart of electromagnetic theory
Because they describe all electric and magnetic fields throughout the universe
Let us now take a look at the order of presentation for the course
We will first begin by exploring electric charges, positive and negative charges.
We will see how these charges interact with one-another
Then, we will see that the reason for those interactions is the electric force
Which we can represent by a vector, starting on a given charge and pointing in a certain direction, depending on the orientation of surrounding charges and the forces they produce
Then we find out that the electric force comes from the electric field
And that they are related to the fundamental property of charge and point inwards (negative charges) and outward (positive charges) in all directions
Then we explore electric flux, which is like the air coming out of a blow drier; it will increase if more power goes through it
Likewise the more charges there are, the more electric flux present at a given region
Then, we delve into voltage, which is a little bit more intuitive, because it's more on the engineering side, than physics side
The second part of the course relates to circuits
We will start off with capacitance, physically and application-wise
Then we will see how circuits containing capacitors actually work
After that, we look at electric current
Then we will learn how to use the idea of resistance and resistors as components in circuits
Then we learn about circuits containing resistors along with capacitors which have many applications, such as timing circuits in digital and analog systems
In the third part of the course we learn about magnetic forces and fields, and induction, which is important for making electric generators and lighting up the earth.
After that, we learn about inductors and how they can be used as passive components like resistors and capacitors
Which will have applications such as RL circuits
And perhaps more importantly, RLC circuits, because when an alternating current is applied to them,
An application such as making a radio can be utilized.
Then we look at the transformer,  which is very important in stepping down the line voltage for household use.
The last part of the course involves magnetic induction, which is very important
And after that, we look deeply into the meaning of Maxwell's equations
And realize that electromagnetic waves are what we know as light
And then we get to Geometrical optics, which involves reflection and refraction of light, and lens/mirror combinations, which are all generally simpler than the rest of the course
I will see you all in the next video, where we start off by analyzing charges.
