Ppismp Sem 2 Physic -circuit

Introduction

Physics is a basic science encompassing a wide variety of subjects, ranging from atom to galaxies and even into the miniscule world of subatomic particles. As such, physic serves as the foundation of the study of all physical science and engineering. Every day that we see many things like the car moving and the fruit drop from top of the tree, that is the physical action. We know that every action that we do is also the fundamental of physic, for example when we carrying a school bag or pulling rope of our cow. The action that we do and done before and now are physic. Physic is the pure knowledge that relate to our life as we apply it for every day. Electric current is the result of the flow of charges. If electric charges flow in one direction without reversing direction, the current produce is called direct current, DC.if the charges reverse their current produce is called alternating current,AC. Direct current is used in most portable or battery –operated device such watches, hand phone and calculator. On the other hand, alternating current is used in most household and industrial appliance such as electric kettle, hair dryer, radios, and refrigerator.

AKNOWLEDGEMENT

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First of all I would like to thank to The Almighty Allah S.W.T because giving me an opportunity to finish my assignment and help me to succeed the task that have been given to me .Then, I would like to thank to our lecturer also our tutor Mr.Zamry Bin Ibrahim because he gives me the task and tell us what to do in order to finish the task. I also would like to thank to my fellow friend because give me support and information in order to find the resource that is useful to my assignment. Soon also to the person who also involve behind me to finish up the assignment according to time that has been things like our given. In this assignment I learned that our ability is actually limited, for example in order measure our school field, we need a measuring tape in order to find the length. Same also with the tailor at the tailor shop they need ruler in order to measure the fabric their customer. But in science field we need to know that our limitation can also affect our measurement and experiment result, so we need to know the right apparatus to measure the correct things and determine the accuracy and consistency of the instrument. This is because most of the problem regarding the measurement are actually comes from our self. As a conclusion I would like to thank to everyone and anyone who help me to finish my assignment. Last but no least, I hope I can do better when doing another assignment

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COMPARISON BETWEEN PARALLEL AND SERIES CIRCUIT

What are voltage, current, and resistance? First, we need to define, briefly, some basic ideas & terms.

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Voltage. Macroscopic matter is made of atoms and molecules bound together by electrical forces. The atoms are composed of electrically neutral neutrons, positively charged protons, and negatively charged electrons. In batteries, and other sources of electrical power, positive and negative charges are separated usually by some mechanical process. Since unlike charges attract each other, work must be done to separate them. You probably have already studied conservation of (mechanical) work and energy in Newtonian mechanics. Electrical energy is simply another form of energy, and what we have found is that all kinds of energy can change form, from one kind to another, but the total energy of an 3

independent system is conserved. Recall that energy cannot be created or destroyed, but changed from one form to another. Under the right conditions, we can get back the work we put into separating the charges. A source of electricity is rated by the “voltage”, or work per unit charge which could be recovered if a unit positive charge moved from the “positive” side of the battery or electricity source to the “negative” side. (or, which is what usually happens, a unit negative charge moved from the “negative” side of the battery to its “positive” side). 2.

Current. The flow of charge through a conductor is called the current and it is the rate at which electrical charges pass an observer’s station per unit time is called the electrical current. We will not discuss conductors in depth here, but we will define a conductor as a material which allows charge to pass through it freely. Since Voltage is work/unit charge and current is charge/unit time, we see that Voltage * Current is Work/time, which is power, or the rate at which work is done. The utility company charges by the total work (or power * time). You should know how much power an electrical device can use, and how much power your electrical power source provides, before connecting any device to an electrical power source. Not knowing could lead to circumstance which are both dangerous and costly.

3.

Resistance. Resistance is a feature of a material that determines the flow of electric charge. When charges have been separated onto positive and negative “terminals”, and suddenly the two terminals are touched together, the charges will move very quickly to equalize the charge. In this case, there will be a large spark which corresponds to a huge instantaneous current (transfer of charge over a very short time). On the other hand, if the terminals are in a vacuum, no current will flow between them. Any intermediate situation will give some intermediate current. The “resistance” of a given piece of material placed between two terminals with difference in voltage V is defined as: V = i * R1, where i is the current which flows between the two terminals when the resistance R is connected. R can always be defined in this way. For other materials, R is nearly independent of temperature, the voltage across it, and the current through it. Materials with variable resistance are fascinating both for their function and their construction. If you go on to design electrical circuits you will work with such variable resistor components as diodes and transistors, or you might worry about the breakdown voltage of gases at which current starts to flow. But in our lab today, we will start at the beginning with materials called “resistors”, for which the “resistance” R is independent of current and voltage. That is, a graph of voltage vs current would be a straight line, with slope R. 4

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The Ohm is named after the German Scientist Georg Simon Ohm who experimented with circuits and found the relationship between current, voltage, and resistance. The equation which relates these three is known as Ohm’s law. Circuits There are three kinds of circuits, series, parallel, and a combination of the two, which we will term series-parallel.

Series circuits

In a series circuit all the component are connected one after another in one single path. Figure below show a series circuit where three bulbs L1, L2 and L3 are connected to a switch and a cell.

L1

L2

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L3

Series circuit diagram

Chateristics of Series circuit I = I1 = I 2 = I 3 V = V1 + V2 + V3 R = R1 + R2 + R3

Parallel circuit In a parallel circuit all the component are connected with their corresponding ends joined together at common point to form separate and parallel path. These path are called branches. Figure below show a parallel circuit where the three bulbs L1, L2 and L3 and their respective switches are connected with ends joined at two common points before ends are connected to a cell.

L1 L2 L3

Parallel circuit diagram 6

Chaterictics of parallel circuit I = I1 +I2 + I3 V = V1 = V2 = V3 R = 1/R1 = 1/R2= 1/R3

Comparison between series circuit and parallel circuit Series circuit

Parallel circuit

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Same current at all point

Different current at different path

In a series circuit, the current has only one path to flow. The current leaving and returning the source is not lost. Therefore , in a series circuit, the current is the same at all point, where:

In a parallel circuit, the current has more than one path to flow. Thecurrent from the source split into separate branches. Therefore

I = I1 = I 2 = I 3

I = I1 +I2 + I3 I

I1

I3

I2

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I

Different potential difference

Same potential difference

The potential difference along the circuit is not same because all it is distributed to all the bulb.

The potential difference is the same for all bulbs in the circuit. V = V1 = V2 = V3

V = V1 + V2 + V3

V1

V2

V3

V2

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R = R1 + R2 + R3

R1

R2

R = 1/R1 = 1/R2= 1/R3

R3 V2

PRACTICAL EXPERIMENT 10

Practical

: Electrical circuits

Objectives

: To determine the advantages and disadvantages of series and parallel circuit.

Variable

Manipulated variable:The type of circuit Responding variable:The brightness of the bulb,the reading of ammeter and voltmeter. Fixed variable:Power supply,type of bulb.

Material

:Battery holder,batteries, several insulated wire, ammeter voltmeter and light bulb.

Activity 1 :

Building a simple series and parallel.

Procedure: 1.Both of the circuit are been construct as shown below,using a battery holder,a battery,several insulated wire and two light bulbs for each circuit. 11

2.The wire is connected and the light bulb has been observe. 3.The ammeter and voltmeter is connected in both the above circuit.A table has been construct and the reading has been recorded. 4.One bulb has been unscrew in each circuit.The remaining bulbs has been observed and the readings of both the ammeter and voltmeter has been recorded. 5.Another bulb is connected inseries to circuit A. The remaining bulbs has been observed and the reading of both the ammeter and voltmeter has been recorded. 6.Another bulb is connected in parallel to circuit B.The remaining bulbs has been observed and also the reading of both the ammeter and voltmeter has been recorded.

Result: Experiment activity 1 Power supply = 3 volt Circuit : A(Series Circuit) Observe Voltmeter reading

Bulb 1 Light up 1.2 12

Bulb 2 Light up 1.6

Ammeter reading

0.2

0.2

Bulb 1 Light up 2.5 0.48

Bulb 2 Light up 2.5 0.48

Observe

Bulb 1 (Unscrew)

Bulb 2 Not light up

Voltmeter reading Ammeter reading

Not light up 3.0 0.0

0.0 0.0

Power supply = 3 volt Circuit: B(Parallel Circuit) Observe Voltmeter reading Ammeter reading Unscrew one bulb Circuit : A(Series Circuit)

Circuit: B(Parallel Circuit) Observe Voltmeter reading Ammeter reading

Bulb 1 (Unscrew) Not light up 2.5 0.48

Bulb 2 Light up 2.5 0.28

Add one bulb in each circuit Circuit : A(Series Circuit) Observe Voltmeter reading Ammeter reading

Bulb 1 Light up 1.1 1.7

Bulb 2 Light up 1.3 1.7

Bulb 3 Light up 0.7 1.7

Bulb 1 Light up 2.5

Bulb 2 Light up 2.2

Bulb 3 Light up 2.0

Circuit: B(Parallel Circuit) Observe Voltmeter reading

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Ammeter reading

0.66

0.44

0.2

Question: 1.What happen to the bulbs in a circuit if one of the bulbs burns out? Explain. In a series circuit if one of the bulb burns out the other bulb will not light up.This is because,in order for the electron to move it need a connector in order to complete the moving in a circuit. 2.What happens to the bulb in parallel circuit if one of the bulbs burns out?Explain. In a parallel circuit, if one of the bulb burns out the other bulb can still light up.This is because, when one bulb burns out the other connector allow the electron can be pass through. 3.You are building a string of light using several bulb.How is the brightness of the lights related to whether you connect the bulbs in series or in parallel. When the bulb is connected using the series the brightness of the bulbs are not the same.But if the bulbs are connected in parallel the brightness of the bulb are the same. 4.What happen to the bulbs in a series circuit if another bulb is connected in series to it?Explain. The bulb will light up but the brightness of the bulb is not the same, because the potential difference is divide and are different in each bulbs. Therefore the bulb that connected in series do not have the same brightness. 5.What happen to the bulbs in parallel circuit if another bulb is connected in parallel to it?Explain. The bulb will light up with the same brightness as the other bulb.This is because in parallel circuit share the same potential difference among the bulbs are the same.Therefore it is prove that the bulb that connected in parallel circuit have the same brightness. 14

Activity 2: Building a combined series and parallel circuit. Material

:Battery holder,batteries, several insulated wire, ammeter voltmeter and light bulb.

Variable

Manipulated variable:The type Responding variable:The brightness of the bulb,the reading of ammeter and voltmeter. Fixed variable:Power supply,type of bulb.

Procedure: 1.Using all the apparatus the circuit has been construct as figure below shown.it has been construct by using a battery holder,battery,a switch, several insulated wire and three bulbs. M1

M2

M3

2.The circuit was connected with the switch and the light bulbs has been observed. 3.The ammeter and voltmeter was connected. The potential difference and the current has been measured for each bulb.A table has been construct to record the result. 4.Bulb M1 is removed,the remaining bulbs and the reading of the voltmeter and ammeter has been recorded. 15

5.Bulb M2 is removed the remaining bulb has been observed and the reading of the voltmeter and ammeter has been recorded.

Result: Power supply = 3 volt Observe Voltmeter reading Ammeter reading

M1 Light up 2.3 0.2

M2 Light up 0.4 0.16

M3 Light up 0.2 0.08

M1 Removed 3.0 0.0

M2 Not light up 0.0 0.0

M3 Not light up 0.0 0.0

M1 Light up 1.4 0.18

M2 Removed 1.4 0.0

M3 Light up 1.4 0.18

Removed bulb M1 Observe Voltmeter reading Ammeter reading Removed bulb M2 Observe Voltmeter reading Ammeter reading

Question 1.What happen to the other bulbs in the circuit when bulb 1 is removed? Explain When the bulb M1 is removed,the other bulb in the circuit do not light up.This is because the bulb M1 is connected in series, so when the bulb is removed the flow of electron cannot pass through because there is no connector to complete the circuit. 16

2.What happens to the other bulbs in the circuit when bulb M2 is removed?Explain As the bulb M2 is connected in parallel therefore the other bulb can still light up,this is because when the bulb M2 is removed it only disconnected a part of the circuit but,the other bulb can still light up because the circuit is completed when bulb M1 and M3 still connected.But there is a different between the brightness of bulb M1 and M3,as we know when the bulb M2 is removed,the circuit become series circuit. 3.Would you want the circuit in your home to be series or parallel circuit or a combination of both?Explain your reasoning. In my home I would like to use the parallel circuit. Because by using the parallel circuit in the home we can avoid the problem such as,when one of our light or electric appliance burns out the others still can be used.We can also can save the electrical uses, for series circuit the distribution of the charges are not the same,so the problem that may encounter is the overflow or distinct of electric charges.Sometimes it can also cause the cross circuit. For example we used the same potential difference for series cicuit,the brighter of the bulb only for one bulb but the other are dim.But using the parallel circuit, for the same potential different the brightness of the bulb also the same.Therefore we can also save the money for electrical bills.Many electrical appliances nowdays using the parallel circuit as the concept for the electrical appliances like hairdryer,refrigerator or the light.So, it is suitable for my home use the parallel circuit.

Conclusion: From the information that you collected an observed in practical, make a conclusions about series and parallel circuit.

In series circuit, the current that passes through each bulb is the same. The potential difference across each bulb is also same as the bulb are similar. The sum of the potential difference across each bulb is the same as potential difference across the battery. 17

In parallel circuit, the bulbs are connected in parallel to the battery and share the same two points therefore the potential difference across each bulb is the same as the potential difference across the battery.The total current that flows in the circuit is the sum of the currents that pass through each bulb in separate paths. In series circuit,the circuit will break off if one of the bulb is removed.The ammeter reading is zero as no current passes through it.The potential difference across each bulb is also zero as no current passes through it. In parallel circuit, only the path in which the bulb has been removed will break off.The current can still flow through the other path.The potential difference across the bulb is still the same as the potential difference across the battery. The bulb in parallel circuit light up brighter as compared to the bulb in series circuit.This is because in parallel circuit, the potential difference across each bulb is higher as compared to the potential difference of each bulb in series circuit.The bulb that light up brighter indicates that the current that passes through it is larger.

REFLECTION

Thank to The Almighty Allah S.W.T as I can finish my biology assignment on time finally. Our lecturer gave us this task early in February and to finish for one month from En Zamry Bin Ibrahim and we had told to hand in the task on 22 Mac 2009. We admitted that at first, we felt so blur and a little bit nervous because we do not know how and what to do in doing this project. Along the way, in doing this project, I gained a lot of knowledge about the series and parallel. A few problems occurred along 18

the time we attempt to finish this task. Besides, I also do not understand what to do at the beginning of the project. After I search the information from internet, and do some discussion with my friends with my lecture. I could understand and imagine what I should do actually. During the experiment for the series and parallel circuit, many problem the we all encounter. Such as when the circuit arte connected only one bulb or no bulb not light up.Then, we change the position of the bulb and using a shorter wire. The parallel circuit sometimes the bulb cannot light up brighter. After adjusting the wire in the circuit and using other dry cell the circuit light up. We also have a problem evolving the reading of voltmeter and ammeter. Sometimes the reading is quiet confusing. Certain voltmeter has no systematic error but certain are not in good condition, therefore the reading that can only take place are affected to the error. Some reading are affected with the parallex error or wrongly jot down the result and cause a miss understanding about the result. Certain experiment can be done in good manner if all the member and precision are take place.Doing the experiment cannot done by wrong way and on our own We must follow the right procedure and also all the result must be in the right condition. From all above, honestly I feel happy and enjoy doing this task because it relates with our life. I learn that the new invention are very meaningful and has their own advantages and disadvantages.If we only know our life are filled with difference and something that are actually relate to our life ,of course it is science.By all of this words I prefer to say thank you to all of the member and colleague who support me.

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List of picture from practicle List of apparatus

Bulbs

Battery

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Bulb holder

Battery holder

Wire

Ammeter

Voltmeter List of circuit

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Series circuit

Parallel circuit

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APPENDIX

Bibliography Elias Saion, 2000, Fizik Matrikulasi Jilid 2,Selangor Darul Ihsan Poh Liong Yong, S.Nagappan, 2003, Physic For STPM Volume 2, Selangor Darul Ihsan David Sang, 2002, Cambridge Advance Series Physic 1, Cambridge University Press 2002 Dr.Zainal Abidin Sulaiman And Co, 2005, Physic For Matriculation Semester 1 And 2, IPTA Production, Selangor Darul Ihsan Chang Lee Leong,Koay Kheng Chuan,Yew Kok Leh, Focus Excel Physics Form 5,2007, Penerbitan Pelangi Cast, C. Vance, Where Does Electricity Come From?, Barrons Educational Series, Inc. Hauppauge New York, 1992. Internet source http://www.ndt-ed.org/EducationResources/HighSchool/Electricity/parallelcircuit.htm 23

http://physics.bu.edu/py106/schedule.html http://www.ndt-ed.org/EducationResources/HighSchool/Electricity/directcurrent.htm http://www.allaboutcircuits.com/l_sitemap.html www.pasoschools.org/prhs/pasohigh/classes/Fairbank/public.www/homepage/physics/S er%20&%20Para.doc www.wikipedia.org/parallelcircuit www.wikipedia.org/seriescircuit www.google.com/search/paralleland series circuit

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