FOREWORD 1 wish to congratulate you for securing admission into this great University, I also want to remind you that you are not admitted because you are the best among all that wrote WAEC, NECO, NABTEB, JAMB etc. There are so many people out there with better results, very intelligent and more hard working, yet were not offered admission had nobody to sponsor them and so could not come. That you are holding this practical manual today, is a sign that God has favored you. I therefore encourage you to work had so you will become the pride of your family, your department, KSUSTA, this nation and your generation. One of our bbjectives in this department is to; “raise strong professional, reliable and dependable graduates who can champion the course of Physics-research within and outside Nigeria”. It is in view of this, that this practical manual was designed. I once read from a book that! “What I hear, I forget, ‘What I hear and see, I remember, What I hear, see and do, I understand.” This manual is aimed at enhancing your understanding of Physics; it will guide you and help you drive home the basic principles, theories and concepts of Physics that you are thought in your various lecture halls. I encourage you to ensure that you participate fully in all the practical's, ask questions and ensure that you always write your reports immediately after each practical before leaving the laboratory. Remember, you can only understand whatever you hear, see and do. Iwish you greattime inthe laboratories.” Once again welcome to the Department of Physics where we explore and understand the Universe. Dr. Benjamin Wisdom Joshua. Head of Department (Physics) This is the third edition of “EXPERIMENTAL PHYSICS MANUAL) for first year students. Itshowcases the BASICS in Physics Experiments leading to a more robust understanding of all Practical Courses. It is therefore pertinent that this guideline would tremendously assist towards impacting positively to all students offering PHY 108. As I wish the students success in conducting all Experimental courses in Physics Laboratories, I urge them to abide by this. SAFETY BEGINS AT THE ENTRANCE OF ALL LABORATORIES, ENSURE SAFETY FIRST. > Thank you and good luck to youall. Engr. MLNayayi Chief Technologist Department of Physicshofore commencing to work on a laboratory experiment, a pret stu "preliminary report” has o include the following information; BEY Udy report has to be 1) Name and: number of the experiment. = Prepare 2)Purpose of the experiments. 3) Diagram. 4)Data/Results tables (to be completed when performing the experi), Inparticular, pay attention to the following points: reearmpose’s ofthe experiment have tobe well defined and clear tof . a peto the Instructor reading the report later on (when its submit Person performing the expen, Whe writer shall not assume thatthe reader is familiar with the experis§Bnt. The prelimi ie Nrwe intend to prove agiven rule or equation, orto examinea sfutionto. problem, or sats aset of measurements. ™, OF, again, to perform, Rr z i ELECTRICITY” Electricity is the flow of moving electrons. When the electrons flow it is called an el aceretand why electrons flow you need tounderstand that atoms eantose electrons bynubbingspiseen material, Conductors, Insulators, and Electron Flow The electrons of different types of atoms have different degrees of freedom to move around, With some typeset ‘has metals, the outermost electrons in the atoms are so loosely bound that they chaotically move ‘ween the atoms of that material by nothing more thap the influence of room-temperature het ‘unbound electrons are free to leave their respective atoms and float aroundintie materials, suc in the space be energy. Because these virtually space between adjacent atoms, they are oftencalled free electrons. 4. In other types of materials such as glass, the atoms’ electrons have little freedom to move around. While external forces such as physical rubbing can force some of these cleggrons to leave their respective atoms and ‘within that material very easily. transfer to the atoms of another material, they do not move between a Conductivity is determined by the types of atoms in a material (the mgpnber of protons in each alom!s nce Getermining its chemical identity) and how the atoms are linked togedier with one another. Material vvithich electron mobility (many free electrons) are called conductors, while materials with low electron mobility (ew orno free electrons) are called insulators. Hereare a few common examples of conductors and insulators: Conductors: Silver, copper, gold, aluminum, iron, steel, brass, Insulators: Glass, rubber, oil, asphalt, fiberglass, porcelain, c wood, plastic, air, diamond, pure water For instance, silver is the best conductor in the “conductors” list, offering easi 0 other material cited. Dirty water and concrete are also listed as conductors, but ‘these materials are subs less conductive than any metal. forthent® Ifwe want electrons to flow in acertain direction toa certain place, we must provide the proper path tt move, just as a plumber must install piping to get water to flow where he or she wants it to flow. To facil wires are made of highly eonduetive metals such as copper or aluminum ina wide variety ofS Remember that electrons can flow only when they have the opportunity to move in the space betws of a material. This means that there can be electric current only where there exists @ Lpoert resea f0 concuctive material providing a conduit for electrons to travel through. In the marble analogy, me en on info the left-hand side of the tube (and, consequently, through the tube) ifand only if he tube i jst Ble right-hand side for marbles to flow out. Ifthe tube is blocked on the right-hand side, the marbles 00% up” inside the tube, and marble “flow” will not occur. The same holds tue electric current thectT how oh rote , trons requires there be an unbroken path to permit that flow. Lets Ipok at adiagram bronze, mercury, graphite, dirty ‘water, concrete eramic, quartz, (dry) cotton, (dry) papes (a) ier passage for electrons than a) Recaps. of wire, Since which ie wichin tis agouree A thin, solid line (as shown above) is the i i ies a a conventional symbol for a continuous piece made of a conductive material, such as copper, its constiuent atoms have many free electTONs move through the wire, However, there wll never be a continuous or uniform flow of elect unless they have a place to come from and a place to go. Let's add a hypothetical ect stom , a of.TASTY ERAGTICAL “Destinations UENWSULE TOE) BOOK - Electron - a‘ rhe Electron ‘ jurce > Destination left-hand side, electron flow through However, the flow will be interrupted No flow! Electron Destination ' °s of wire, the once-continuous path has | ‘on. This is like cutting a water pipe in two sno exit outof the pi sin one piece, pe. In electrical terms, and now that continuity is broken If we were to take another piece of wire le wire leading to the Source, we would one ‘ding to the Destination and simply make physical contact with the | *¢ again have a continuous path for electrons to flow. The two dots in| ween the wire pieces: the diagram indicate physical (metal-to-metal) eontecs —— er Electron +». Source inuity from the Source, tothe newy-made connection, down, tthe right, and up tothe Ree ay som ting a “\.c' fitting in one of the capped-off pipes and directing wate Destination. This is analogous to putting a i 2 tifough a Sy segment of pipe to its destinatioc. Please take note that the broken segment of wire on the righ hand ide bi us leone flowing through it, beca'-> it is no longer part of a complete path from Source te Destination. - _ . enone a “ P ithin wires dus to tis electric current, r-carryin FEE a rencusty corms aca aoe by prolonged sve. Electrons do encounter some degree 0 ee nastid) ove hiweees, and this friction can generate heat in « conductor. This sa topie well explore jonas : : much greater detail late.. How Voltage, Current, and Resistance Relate is il that cause: VOLTAGE ial difference, is described as the pressure or force t i ), or potential it ‘y " ¥ bolized wit Seer ee oe oo uaa Games ad eae ula vobage rub wi electrons to iteton laboratory equipment or schematic dingrams, the voltage is often repre capital B, while on lal y 1 through aconductor. CURRENT is deseribedasthe movement of fee eesron through ondstn | Electron current, or amperage cepial 1, while in the laboratory or on schematic diagra formulas, current is sym! tousea capital Ato indicate amps or amperes.} —_ — eM MEENTT en on). ' RESISTANCE Resistance 1s defined as the mates tal depend @® the opposition to current fffvw. The amount of opposition to current fle ines a | i oe the amount ot available free electrons it contain oe the ypc obec neat the symbol iRe It to eave thtavh the material Resistance is measured in ohms and is repees emus \ One ohne n defined as that amount of resistance that will limit the curr akortiiaadl nteetinn te 1 the potential difference (voltage) applied to the conductor is one shortand notation for whim 1 the Grek letter capital omega (a). Ifa voltage is applic c ce of the conductor. Thi higher the c istance, the lowe Here are the stand. taye, and resistance: the resistance, the mount of current How he current flow, Unit of Un Measurement Abbie vlation Ampere (amp?)| A | is named after famous experimenter in electricity: The amp after the Frenetman \essandro Volta, and the ohm after the German Georg Simon Ohm. seoften taught in the beginnings of electronics courses but used infrequently afterwards, is the unit of the coulomb, °¥ his « measure of electric charge proportional to the intfer of electrons in an imbalanced sta, One cowl. of charge te ‘equal to 6,250,000,000,000,000,000 sarvons, The symbol for electric charge quantity is the, capital leiet “Q,” with the unit of coulombs ceerated by the capital letter “C.”Itso happens that the unit fr electron low, the amp, iseqi aoe rons passing by a given point in a circuit in I second of time, Cast in these terms, current is the rate of tlectric charge motion through aconduetr Bach unit of measurement ‘Andre M. Ampere, the volt after the Its! ‘One foundational unit of electrical measur pins Law tis Oh:'s principal discovery was that the amount of clectrie current through a metal conductor in @ circuit in i his to the voltage impressed act ns it, for any given temperature. Ohm discovery inthe form of asimple equation, describing how sitaye, current, and resistance interrelate: V=IR;[=V/R; R= VA | or er In this algebraic expression, voltage (1) equal to current (1) multiplied by resistance (R). Using algebre ‘we can manipulate this equation ito two variations, solving for Land for R, respectively: oe r= R 1 Let's see how these equations might work tohelpus analyze simple circuits: ” ieee C—O)~ Electric tamp (glowing) electron flow Intheabove circuit, there is only one source of voltage (the battery, toehirent (the lamp, on the right), This makesit very easy to apply of the three quantities (voltage, current, and resistance) inthe third. ‘onthe left) and only one source of resistance Ohm's Law. If we know: the values of any two ircuit, we can use Ohm's Law to determine the In this first example, we will calculate the amount of current @ ina circuit, given values of voltage (E) and resistance (R): =4A In this second example, we will calculate the amount of resistance (R) in a circuit, given values of voltage (E n this secon , and current (1): im4a a4CR te PHYSICS 108 PRACTICAL MAN ‘What is the amount of resistance (R) offered by the | lamp? . Inthe lastexample, we resistance (R): BiVeu values of cur ag ‘Whatis the amount of voltage provided by the battery? ALTERNATING CURRENT Alternating Current or AC current is almost universally used for home electric power ands, therefore, the ki this article is primarily concemed with. In an AC circuit, the amount of voltage applied to fovea constantly changing from zero to a maximum and back to zero in one direction and then from zero to maximum and back to zero in the other direction. Each complete change from zero to maximum to zero inone direction and then zero to maximum to zero in the opposite direction is called one hertz (formerly cycle). DIRECT-CURRENT Direct-Current or DC Direct current is most commonly found in homes in the form of electrical energy storedin batteries. In a DC circuit, the amount of voltage and the direction of application are constant. The chemical energy can be in wet form, as in your car battery, or in dry form as in flashlight and transistor-radio bateris. ‘Some batteries are designed to be recharged from an AC source. andthe Sine PROCEDURE: . Using the circuit diagram, connect the dry cell (Two 1.5V cells) with the re Voltmeter in parallel by introducing 1.0 Ohm, 2,0 Ohms, 3.0 Ohms, 4.0 ‘measure and record the corresponding voltage on the voltmeter. ——__-- a ssistors in series arrange? ‘oan 5.0 ohms and indsb Stes MONTE CAO UAU/REPORT BOOK PRECAUTION — Never close the switch at zero-ohm on the tesistance box, Do time to avoid over heati; Hot hold the switch closed forgo long period of the resistorand. overdrawing energy frombatery Tabulate all the measured values, GnaPn. graph of Noltage against the Resistances = 1 Gisione slopeofthe graph ic Intercept. 2 Indicate the: ‘on the vertical axisMENT OF RESI®BORS . “Series” connection i that components are connected end-to-end ina lind form a single path for, el flow through the circuit, lectronsy, In.this set of experiment, the resistance of resistors in a series combiggiiion will be measured, In again measurements willbe made tochusk the validity of the assumption used ierivethetheoretiat itn, the total resistance of series combination, ° ession NOTE: Before making any connections, make sure the power supply is switched DIAGRAM EXPERIMENT 1.0 DETERMINING THE CURRENT FLOW INA crecurr. AIMS: VERIFICATION OF OHMS LAW APPARATUS Apowersupply/Two 1.5V dried cell, Resistor, Voltmeter, Connecting wires, DIAGRAM: R1 R2, R3 PROCEDURE: Connect the first, second and third resistors in series, Connect the series cambination first to the voltage supply, next to the ammeter and then to the voltmeter or alternatively a multimeter to serve as a voltmeter. With the Power supply turned OFF, turn the current control on the power supply t half its maximum values. Turn the voltage control completely down to zero before¢aening the power ON, Tie voltmeter should be set to the 20% (DC) maximum scale and the ammeter should be set to the: 200mA (DC) maximum scale. However tum the power ON, and increase the voltage slowly until 5.0¥, is displayed on the power supply. Record the voltage and the current. Continue slowly increasing the voltagp until you have voltage and current measurement for 10V, 15V, 20V, and 25V. i. Disconnect the voltmeter, Use the voltmeter to measure the ‘voltage drop @@ross each individual resistor for te last trial, when the total voltage is about 25V, Record these voltages. In adgftion, record the total voltage and! total currentiin the circuit, Reset the voltage to zero and tum the power supjiy OFF. » e PRECAUTION a A ri of Never close the switch at zero-ohm on the resistance box, Do not hold witch closed for so bey wien time to avoid over heating the resistor and overdrawing energy from battegg) Avoid parallax and zero aennn ahem ES LLNS TOUT JREPORT BOO) taking reading from voltmeter and ammeter. “Tabulate all themeasured values. - GRAPH: Plot graph of Voltage against the Resistances L Calculate the slope of the graph 2. Calculate the Voltage drop in each TesistorSele AWN IAS RATS huree, pluy key, switet Plug key, switch, Resistance ao voltmeter INTReDY TION i “Parallel” connecti t Purely paratiel gaat oH the other hand, is that all components are Bonnected across each other's lead, Components ane eit Mere are never more than two sets of electrically common points, no matter how nt? see Me connected, There are many paths for clectrons td flow, but only one voltage across x In OF esPerieht the foal resistance of resistors in parallel edfnbination will be measured, In ad otal earns Will be made to check the validity of assumptions usd to derive the theoretical expression Stal resistance of parallel combination t NOTE: | Before making am c x EAGAN) Omnections, make sure the power supply is turned pf. thet PROCEDURE: Connect the first, second and third resistors in parallel. Connect the-parallel combination first to the power supply, next to the voltmeter, However, with the power supply turnedoff, tum the current control: ‘on the power © supply to half its maximum value. Tum the voltage control completely down to zero before turning the power on. The voltmeter should be set to the 20V (DC) maximum scale, andthe ammeter should be set to the 200mA (DC) maximum scale. Tum the power on, and increase the voltage sloggly until around one voltis display onthe voltmeter. Measure and record the voltage and current displayed, Cofttinue slowly increasing the voltage until you have voltage and current measurements for about 2V, 3V, 4V aifl SV. Disconnect the voltmeter. Use the Voltmeter to measure the voltage drop across each individual resistorifor the last trial, when the total voltages about 5V. Record these voltages on your data sheet. Inaddition, recordathe total voltage V and the total curentin the circuit. PRECAUTION ‘odot Never close the switch at zero-ohm on the resistance box. Do not hold the switch closed for so long period time to avoid over heating the resistor and overdrawing energy from battery. Avoid parallax and zero eror when. taking reading from voltmeter and ammeter. ‘Tabulate all the measured values. GRAPH: . Plot graph of Voltage against Current & 1. Calculate the slope ofthe graph ® 2. Indicate the Intercept on the vertical axis & L