Like the wheatstone bridge, the potentiometer exists in both slidewire and box forms. You can also get class xii practicals on biology, physics, and physical education. Potentiometer, 012 volt power supply, flashlight, standard cell, galvanometer, double pole switch, slide. Potentiometer works on the principle that when a constant current flows through a wire of uniform cross sectional area, potential difference between its two points is directly proportional to the length of the wire between the two points. Potentiometer study material for iit jee askiitians. In above figure ac is a 1m long wire made of maganin or constanan having uniform area of crosssection.
Potentiometer experiment compare emfs of two cell by anshu kapoor duration. Potentiometer is an accurate instruments used to compare emfs of a cells,potential difference between two points of the electric wire potentiometer is based on the principle that potential drop across any portion of the wire of uniform crosssectional is proportional to the length of that portion of the wire when a constant current flows. Measurement of resistance using potentiometer circuit globe. Class 12 cbse physics practical comparison of emf of two.
The accuracy of the voltmeter cannot be increased beyond the limit. Use a potentiometer to vary the voltage across the bulb measured by the voltmeter v. This can be done by comparing the unknown resistance with the standard resistance. Potentiometer, a leclanche cell, a daniel cell, a two way key, a resistance box plug type 0. Comparision of emfs please use headphones for better sound. Connect the positive pole of the battery to the zero end p of the potentiometer and the negative pole through the oneway key, low resistance rheostat and the ammeter to the other end of the potentiometer q. Finding the ratio of the emfs of two cells by a potentiometer. Figure below shows a schematic diagram of a meter bridge. Jan 2, 2020 hemant more physics advantages of potentiometer, comarision of emf of cell, construction of potentiometer, current electricity, individual method, internal resistance of cell.
The following setup, called a potentiometer, accomplishes this. Potentiometer physics 184 experiment 3 potentiometer. Apparatus a potentiometer, a battery or battery eliminator, two oneway keys, a rheostat of low resistance, a galvanometer, a high resistance box, a fractional resistance box, an ammeter, a voltmeter, a. To draw the iv characteristic curves of a pn junction diode in forward bias and reverse bias. With the knowledge of the basic principle of potentiometer and from what i have learnt from my physics textbook, the sum of the two emfs is proportional to the length given in the first case, and when e2 is subtracted from e1, the result is proportional to the length given in the second case. Potentiometer working, their applications and different types. Determine the internal resistance of a primary cell using a potentiometer. And also it is used to compare emfs of different cells. Role of potentiometer for comparing emf of two cells. Know the p rinciple and method of measuring electromotive force and voltage by learning compensation method.
A onemeter length wire, made of an alloy that has a much higher resistance than that of a similar copper wire, is strung between points a and d, forming the lower part of the circuit. The emf is defined as the potential difference between the positive electrode and the negative electrode when there is no current flowing through the cell or in an open circuit. This is a very basic instrument used for comparing emf two cells and for calibrating ammeter, voltmeter and wattmeter. Comparision of emf using potentiometer experiment study page. It is possible to compare the emf of two cell with a potentiometer. Abstract the main purpose of this experiment is to use the potentiometer to measure the emf of a cell. What should be the sequence of color bands used to code it. To compare the emf of two given primary cells daniel and leclanche cells using a. The null point occurs where the voltage along the wire matches the voltage out of the cell under test.
Measure the emf e of the battery and the emfs e 1 and e 2 of the cell and see if e 1 e and e 2 e. Potentiometer is a simple device used to measure the electro motive force, potential difference across a resistor and internal resistance of a cell. Homework statement in this experiment, were trying to study the characteristics of a light bulb. With a little bit of calculation i get the answer, 4. Electromotive force emf is a measurement of the energy that causes current to flow throughout a circuit. Sensitivity of a potentiometer depends on its potential gradient. To determine the internal resistance of a given primary. But in the process of measuring, it draws a small current from the cell.
It can also use as a variable resistor in most of the applications. A potentiometer made from homogenous resistance wire of length l and resistance r l al is used to changed voltage at an appliance of resistance r find the voltage across and current through a resistor r as a function of the distance x of the sliding contact from the end of the potentiometer. Experiment aim to compare the emf of two given primary cells daniel and leclanche cells using a potentiometer. The potentiometer is a simple device used to measure the electrical potentials or compare the e. The emf of a cell may be defined as the terminal voltage of the cell when not under load, that is.
Sketch a,graph showing variation of resistivity with temperature of i copper ii carbon. Measuring the internal resistance of a battery cell. Potentiometer physics 184 experiment 3 potentiometer object. To determine resistance of galvanometer using metre bridge. Students understand the different components used in the experiment. Repeat the experiment by increasing the current by adjusting the rheostat and record. The terminal voltage of a cell is the potential difference between its terminals. Measur e the electromotive force and internal resistance of a battery with a dc potentiometer. If the potential gradient of a potentiometer is small then the potentiometer is more sensitive and hence more accurate a comparison of emf s of two cells using potentiometer. The combination is connected through a galvanometer and a jockey to a potentiometer. Collect data of vvalues and corresponding ivalues from the ammeter over the voltage range 012 v. The terminal b between the gaps is used for connecting galvanometer and other end of the galvanometer is connected to a jockey j.
A potentiometer is a mechanism used to evaluate the e. In an earlier experiment, a voltmeter was used to measure the. The potentiometer is an electric instrument that used to measure the emf electro motive force of a given cell, the internal resistance of a cell. Determining the internal resistance of a given primary cell. Potentiometer consists of a long resistive wire ab of length l about 6m to 10. Determining the internal resistance of a given primary. The three main applications of a potentiometer are. One terminal of another cell whose emf e is to be measured is connected at one end of the main. The potentiometer is a device mainly used to measure the emf of a given cell and to compare emfs of cells. Compare the emf of the two given primary cells using. The accuracy of the potentiometer can be increased by increasing the length of the wire. To compare the emf of two given primary cells using potentiometer. Unit2 current electricity very sholrt answer questions i mark 1.
A potentiometer is a manually adjustable variable resistor with 3 terminals. Comparision of emf using potentiometer experiment experiment. Theory the purpose of this experiment is to measure the electromotive force emf and internal resistance of a dry cell. Sep 15, 2015 please use headphones for better sound please use headphones for better sound skip navigation. A battery of known voltage e and internal resistance r called supplier battery or driver cell. The potential difference across any portion of the potential of the potentiometer wire is directly proportional to the length of that portion provided. To determine the internal resistance of given primary cell using potentiometer. Nov 26, 2016 to determine the internal resistance of a given primary cell using potentiometer aim to determine the internal resistance of given primary cell using potentiometer. You are required to select a canbon resistor of resistance 47k. Slide wire potentiometer, battery or power supply, rheostat, double poledouble throw dpdt switch, standard cell, unknown cell, galvanometer, key switch and a multimeter. Slide wire potentiometer, battery or power supply, rheostat, double poledouble throw dpdt switch. How will you compare emf of two cells using a potentiometer.
Comparing the emf of a battery cell with a standard cell. Obtain the required expression used for comparing the emfs. Two terminals are connected to both ends of a resistive element, and the third terminal connects to a sliding contact, called a wiper, moving over the resistive element. Two primary cells of emfs e1 and e2 respectively are joined in series with i the same polarity, and ii opposite polarities.
The experiment is repeated using the second cell e2 and the corresponding length 2 obtained. More information can be found on the dedicated page about rheostats. This indicates the value of v is less than e by an amount. Feb 07, 2017 potentiometer is a simple device used to measure the electro motive force, potential difference across a resistor and internal resistance of a cell. To compare the emfs of two given primary cells using a potentiometer. So that the slider can find a null point somewhere along the wire, of course. Apparatus potentiometer, a leclanche cell, a daniel cell, an ammeter, a voltmeter, a galvanometer, a battery or battery eliminator, a rheostat of low resistance, a resistance box, a one way key, a two way key, a jockey, a set square, connecting wires and a piece of sand paper. With the help of the circuit diagram, explain how a potentiometer is used to compare the emfs of two primary cells. To determine the internal resistance of a given primary cell.
To determine the internal resistance of given cell using potentiometer. The purpose of this experiment is to measure the electromotive force emf and internal. Measuring the voltage across a branch of a circuit. For a constant current, the fall of potentiometer along a uniform wire is directly proportional to its length. A potentiometer is an electric device used to measure the emf and internal resistance of a cell, to compare emf of two cells and a potential difference between two points in an electric circuit. Meter bridge is based on the principle of wheatstone bridge and it is used to find the resistance of an unknown conductor or to compare two unknown resistance. Since the reference voltage can be produced from an accurately calibrated voltage divider, a potentiometer can provide.
Nov 26, 2016 to compare the emf of two given primary cells using potentiometer. The relation between potential difference, emf, and internal resistance of a cell is given by. The voltage drop across the known and unknown resistance is measured and by comparison the value of known resistance. Potentiometers work by varying the position of a sliding contact across a uniform resistance. When an ammeter is put in series in a circuit, does it read slightly less or more than the actual current in. Why should the emf of the driver cell in the potentiometer. The emf of the driver oell auxiliary battery in the potentiometer.
Potentiometer, 012 volt power supply, flashlight, standard cell, galvanometer, double pole switch, slide wire resistor, carbon pile resistor. To measure the emf, one has to devise a method that requires zero current ow in the cell so as to eliminate the potential drop across the internal resistance. Potentiometer, a leclanche cell, a daniel cell, an ammeter, a voltmeter, a galvanometer, a battery or battery eliminator, a rheostat of low resistance, a resistance box, a one way key, a two way key, a jockey, a set square, connecting wires and a piece of sand paper. Camparision of emf of two primary cell by potentiometer. Consider the circuit arrangement of potentiometer given below used for comparison of emfs of two cells. Difference between galvanometer and ammeter potentiometer. Potentiometer experiment compare emf s of two cell by anshu kapoor duration. The position of the wiper determines the output voltage of the potentiometer.
Apparatus and material required potentiometer, a leclanche cell, a danie l cell, a two way key, a r esistance box plug type 0 to. This is a very basic instrument used for comparing emf two cells and for calibrating ammeter, voltmeter and watt meter. One form of potentiometer is a uniform highresistance wire attached to an insulating support, marked with a linear measuring scale. In a potentiometer, the entire input voltage is applied across the whole length of the resistor, and the output voltage is the voltage drop between the fixed and sliding contact as shown below. Use the resistor color code in the introductory section of this manual to identify the. E 1 is connected to end a and a negative terminal is connected to jockey through the galvanometer. To compare emf of two given primary cells using potentiometer apparatus. A cell is characterised by its emf when current is drawn from a cell, there is a movement flow of ions in the electrolyte between the electrodes of the cell. To compare the emf of two given cells using potentiometer. The emf of the driver oell auxiliary battery in the potentiometer experiment should be greater than emf ot the cell to be dete,rmined. A potentiometer can also be wired as a rheostat, or single variable resistance.
The potentiometer is a device used to measure the internal resistance of a cell and is used to compare the e. Dec 20, 2017 emf of driving cells is less than that of cells to be measured. The ratio of the emf of two cells is given by, 1 2 h1 h2. Slide wire potentiometer, battery or power supply, rheostat, double poledouble.
Comparison of emfs of two given cells using potentiometer. Potentiometer experiment compare emfs of two cell by anshu. D is connected directly to a, and f is connected to a sliding contact on the. If a sensitive indicating instrument is used, very little current is drawn from the source of the unknown voltage. Potentiometer, leclanche cell, daniel cell, ammeter, rheostat, galvanometer, two way key, jockey, battery or a battery eliminator and connecting wires.
To determine the internal resistance of a given primary cell using cell using potentiometer apparatus. How to measure emf of a cell using potentiometer quora. Using a voltmeter it is possible to measure only the potential difference between the two terminals of a cell, but using a potentiometer we can determine the value of emf of a given cell. The potentiometer wire ab is connected in series with a battery bt, key k, rheostat rh as shown in figure. To measure the emf of an unknown cell using a potentiometer. Apparatus a potentiometer, a battery or battery eliminator, two oneway keys, a rheostat of low resistance, a galvanometer, a high resistance box, a fractional resistance box, an ammeter, a voltmeter, a cell say leclanche cell, a jockey, a set square, connecting. Internal resistance of a cell using potentiometer experiment. A potentiometer is a three terminal device that is used to measure the potential difference by manually varying the resistance. Jan 02, 2020 potentiometer is more sensitive compared to voltmeter. One of the main uses of a potentiometer is to compare the emf of one battery cell with a standard battery cell. A voltmeter is a device used for measuring the terminal potential difference of a cell.
Please use headphones for better sound please use headphones for better sound skip navigation. These potentiometers are used in huge quantities in the manufacture of electronics equipment that provides a way of. First of all the ends of the potentiometer is joined to a battery b1, key k and rheostat rh such that the positive terminal of battery b1 is connected to end a of the wire. It can be used to measure the internal resistance of the cell. A voltmeter is a direct reading instrument while potentiometer is not so. Jul 15, 2014 i dont have a clear perception of how the following question is answered. Two students were performing the potentiometer experiment to determine the emf of a cell using the circuit shown in the figure. Potentiometer experiment compare emfs of two cell using potentiometer class 12th physics experiment by anshu kapoor donate with. To compare emf of two given primary cells using potentiometer. Physics helpline l k satapathy direct current 4 potentiometer experiment 1 errors in potentiometer experiment a g 2. Compare your circuit to the detailed diagram in section iv. In order to calibrate a voltmeter and to contrast the emf of a cell with its terminal voltage. The best way to wire a potentiometer as a rheostat is to connect the wiper and one end terminal together, this prevents infinte resistance if the wiper occasionally loses contact.
641 401 1444 264 627 1400 272 1338 1405 944 540 860 216 200 1439 442 1209 621 1384 365 1347 352 881 406 912 359 1215 632 324 303 557 925 1152 1497 1001 1179