• Electricity: is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge.

• We have two types of circuits parallel and serious.

• Parallel meaning we have more than one pathway.

• Serious circuit meaning we have on pathway.

• Electricity is the result of electrons moving in order to remove a difference in electric charge between two points.

• Of course, when the electrons move, they carry kinetic energy and this energy can be used to do useful work.

Electric charge

• The utility of electrical energy depends on the ability of electric charge to move.

• Electric charges are positive or negative. In atoms positive protons in the nucleus are surrounded by negative electrons.

• Atoms are uncharged because they have the same number of protons and electrons.

• Electrons can be transferred between atoms. Protons are not transferred.

• An atoms becomes positive when it loses electrons. It becomes negative when it gains electrons.

Static electricity

• Electrons can jump from one material to another

• The material that loses electrons becomes positively charged and the material that gains electrons becomes negatively charged.

• These charges can build up on materials.

• Electricity is broken down to static and current electricity.

<aside> 💡 Static electricity: is the buildup of positive or negative charge

</aside>

<aside> 💡 Current electricity : Is the energy of steadily moving electric charge.

</aside>

Current electricity

• Electric devices such as lamps and computers cannot run on static electricity. Instead, they use current electricity.

• The flow of energy carried by electrons is called an electric current.

• The amount of electricity flowing in a circuit is measured as electric current in Amperes, or amps for short

Difference between static and current electricity

Probably on the exam

• The most significant difference between the static and current electricity is the static and current electricity. is that in static electricity the charges are at rest and they are accumulating on the surface of the insulator.

• Whereas in current electricity the electrons are moving inside the conductor.

• The static electricity uses in pollution control machine, in machine painting, xerography etc.

• The metallic plates of the pollution control machine convert the dirt particles into static charge.

• The static dirt particles attract towards the opposite charge plate of the pollution control machine. This, accumulate in the device.

• The current electricity use for performing the mechanical work like running the fan, motor, etc.

Circuit

• Electrons make up the moving electric charge of the current electricity.

• These moving electrons must have a path to follow. A pathway for electrons is called a circuit.

• Electrons flow steadily only when the circuit is closed, which is when the circuit forms a complete loop.

• So when a circuit is closed, electric devices in the circuit will be on and running. If a circuit is open, electrons cannot flow, and electric devices in the circuit will not run.

Parts of a circuit

• Resistance is a measure of how much an object opposes the flow of electric current.

• The wires used to connect the parts of a circuit have low resistance. They are good conductors.

• A common energy source is an electric cell, or battery.

Series circuits and parallel circuits

• Series circuit: is a circuit that has a single pathway for electrons to follow

• Advantages of series circuits-Simple to design and build

• Disadvantages of series circuits- If one light goes out, they all go out; as more lights are added, they become dimmer.

• Parallel circuits: is a circuit that has more than one pathway for electrons to follow.

$I= 9/t$

$Q= I .t$

$T= q/I$

<aside> 💡 Memorise!

</aside>

I: Current (A). (Amperes or Amps or A)

Q: electric charge (C)

T: time (S)

Example 1: When 5 coulombs flow through a resistor for the duration of 10 second, calculate the current.

Solution:

$9= 5C, t= 10 , I=?$

$I= 9/t = 5/10 = 0.5 A$

Example 2: Find the unknown quantity:

a) I= 0.4 A , Q= ?, t=205

I = q/t

Q=I.t

Q= 0.4 x 20

= 8c

b) I=? , 9= 240 C, t=300 S

I = q/t

c) I= 2a, q = 400 c, t=?

I= q

t= q/I = 400/2 = 200s

I= q/t

Potential difference ( voltage)

The difference in electrical energy caused by a charge difference between any two points is called potential difference (P.d) . since it is measured in (volt , (v) ).

Potential difference (v) energy difference (J) / Charge (c)

$P.d (voltage) = E/q$

$P.d (voltage = E/q$