UNIT 4Standard No:23

LESSON 2

ELECRICITY

types of circuits

Series CircuitParallel Circuit

Ammet

erVoltmeter الجهد جهازقياس

الكهربائي

التيار شدة جهازقياس

Series Circuit

Parallel Circuit متوازية دارة

متسلسلة دارة

There are 2 types of circuits

Series Circuit Parallel Circuit

Series CircuitSeries Circuit: the components are lined up along one path. If the circuit is broken, all components turn off.

Parallel CircuitParallel Circuit – there are several branching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off.

There are 2 types of circuits

Series Circuit Parallel Circuit

Series Circuit: the components are lined up along one path. If the circuit is broken, all components turn off.

Parallel Circuit – there are several branching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off

Series circuit

In series circuit with two lamps, if one breaks the other goes out, too

Parallel circuits

In a parallel circuit with lamps on separate wires, if one breaks the other stays lit

10

measuring currentElectric current is measured by sing an……………………….. connected

in .................... in the circuit.

Activity:1- Use the items you have and make complete circuit 2- Add the ammeter to the circuit .3- Did the reading in the ammeter change? ……….

A A

The number of electrons moving through a circuit.

The electrons carry electrical energy.

Electric current :

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SERIES CIRCUIT• current is the same at all points in the circuit.

measuring current

2A 2A

2A

PARALLEL CIRCUIT• current is shared between the components

2A2A

1.5A

0.5A

Electric current :

The number of electrons moving through a circuit.The electrons carry electrical energy.

13

measuring potential differencePotential difference is measured by sing a……………………….. connected

in .................... in the circuit.

Activity:1- Use the items you have and make complete circuit 2- Add the Voltmeter to the circuit .3- Did the reading in the voltmeter change? ……….

V

V

Potential difference :It is the difference in electrical energy between two parts of a circuit, measured in Volts.It is provided by a source (battery) which causes the current to move through the circuit.

14

measuring potential difference

SERIES CIRCUIT

PARALLEL CIRCUITvoltage is the same

in all parts of the circuit.3V

3V

3V

voltage is shared between the components

2V 1V

3V

(Potential Difference (voltage

It is the difference in electrical energy between two parts of a circuit.It is provided by a source (battery) which causes the current to move through the circuit.

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Activity1

V V

6V4A

A

Aa)

V

V

6V4A A

A

A

b)

Write the missing numbers of volts and ampere:

ACTIVITY 2:Use the table below to draw a graph between the current and the potential difference.

10 8 6 4 Potential difference

8 6 4 2 current

potential differences

current

0 2 4 6 8 10 12

10

8

6

4

2

Direct proportion طردية عالقة

potential differences

current R=

R depends over the wire so it was called Resistance and it’s measurement unit is ohm Ω

Ohm’s law :

In electrical circuits, Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points, and inversely proportional to the resistance between them.

R I

V

Georg Simon Ohm (16 March 1789 – 6 July 1854) was a German physicist. As a high school teacher, Ohm began his research with the recently invented electrochemical cell, invented by Italian Count Alessandro Volta. Using equipment of his own creation, Ohm determined that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current – now known as Ohm's law.

R I

V

What is the amount of current (I) in this circuit?

V

V

What is the amount of resistance (R) offered by the lamp?

V

V

R I

V

So Ohm was named after the scientist

Home workFind out where did the words volt and ampere came from ?

Adding resistances in series

•Each resistance in a series circuit adds to the total resistance of the circuit.

Rtotal = R1 + R2 + R3...Total

resistance(ohms) Individual resistances

(Ω)

Open physics for you pg:208 -209 and try to solve

problemsExample 1 and 2

ACTIVITY :The flow of electrical charge

around a circuit is called the …a) raisin.b) battery.c) current.

The symbol represents which electrical component ?

a) A switch.b) A bulb.

c) An ammeter

Review

ACTIVITY :Look at each diagram below, If you think the bulb or bulbs will light, put a tick in the box. If you do not think the bulb or bulbs will light, put

a cross in the box:-

Review

A

End of lesson2