Structure of Matter.

The world around us is created form small elements known as the atoms. Atom helps us to realize the basic theory of charge. If we talk about basic structure of atom we know that it have a nucleus, which consists of protons and neutrons . The nucleus is surrounded by electrons. Different atoms can have different number of electron based on the atomic number

Atom and its Components

Atoms can be divided in general in to four parts .

1. Electrons

2. Nucleus

a. Proton

b. Neutron

Electrons

The electrons have negative charge on them . And movement of the electrons present in valence cell are the general reason of electricity .

Nucleus

Nucleus houses neutron and protons

Protons

Proton is the positive charge. For a long time it was considered by scientist that, the movement of proton caused current flow .

Below is a specific chart that help indicates different values of particles

Remember

Like charges always repel, and Opposites attracts

Types of Materials

Materials can be divided in 3 types. (how ever scientists will be coming up new types and subgroups every new day , but for this text , we are fine with three).

They are Conductors, Semiconductors and Insulators

Charge and Current

We have already discussed the charged particles that are present inside a atom.

So if start gathering lot of positive particles on one plate we will end up with a pool of positive charged particles

If now we apply some force to push this charge ….. the charge will moving forward .

So now the charge becomes “MOVING CHARGE”. Same scenario can be applied on negative charged particles.

Now we have three points to discuss from above discussion .

· Charge

· Moving Charge

· And force that move charge

Charge

In SI system the unit of charge is coulomb ( C ) . One Coulomb has a charge if we collect 6.24×10^18 Electrons or if we gather 624000000000000000000 electrons . We will have one Coulomb. This is a fairly large amount. Now it can be due to positive and negative charges. The Quantity of charge is represented by Q or q

Current.:

The moving Charge is called “Current”

It have a unit of Ampere

Or

It is the amount of charged that is passed through point A to Point B in a particular time and is represented by I

I=Q/t

A real life example to understand in our power lines. Think how they transfer charge to our houses

We can accumulate charge by transferring electrons. The amount of charge is denoted by the letter Q and its unit is the Coulomb (denoted C).

Normally constants levels of charge , voltage and current and other quantities are represented by capital Alphabets like

Current AC

In above material we talked about current . as amount of charge passed in a wire in particular time. How ever we may have cases , where charge is also varying. Hence we will have a charge changing its value continuously in such cases. In such cases the current may be defined as “RATE OF CHANGE OF CHARGE W.R.T TIME”

Note the values here are represented by small vales. Such current is called AC Current

Some errors while representing current

For a time depending current we may define it as,

Example 1

Example 2

Example 3

 

 

Example 4

Example 5

– (t=1 and t =3)

=96 C