Physical quantities and units kinematics dynamics mass, weight and density turning effects of forces pressure work, energy and power kinetic model of matter transfer of thermal energy temperature thermal properties of. Emf is the electromotive force or the electric fields which are produced by the battery or a source of the energy in the circuit system. Understanding the difference between the two and what emf means gives you the tools you need solve many problems in physics and electronics, and introduces the concept of the internal resistance of a battery. When you have completed the booklet go to the schools website and find the relevant mark scheme and mark your work. Technology produces much more intense electromagnetic fields, and these fields can cause health risks. Electricity as physics 5 revision lessons, powerpoint. Pdfdownload resonance important formula booklets for jee. A 5 lesson electricity revision series 100 min lessons. But if you live where there is cell phone service or power lines, for example, you are exposed to. Higher physics electricity notes teachers booklet mrs physics.
This is a booklet for low ability students covering a lot of the forces module. The variable resistor is altered and readings of potential differences across the terminals of the cell and. Potential difference is the voltage across the terminals of the battery when the current is being drawn from it to an external. Actually my sir asked me the definition of emf so i just tell him that suppose a resistancer is connected across the terminals of a battery. This terminology dates back to a time when energy and force were confused. Models of the known universe stars and galaxies structure of the universe information from stellar observation how the universe may evolve relativity. Electromagnetic induction cie igcse physics revision notes. The internal resistancer of a cell is a very small resistance. Direct current flows in one direction and has one value.
Electromotive force emf is not a force, but the energyperunitcharge required to separate electrons in an electrolytic cell. Motional emf also occurs if the magnetic field moves and the rod or other object is stationary relative to the earth or some observer. Higher physics student resources lesmahagow high school. Manage your own revision with stepbystep support from experienced examiner and author richard woodside.
Designed to do with year to recap knowledge before a level examinations in summer, however could be used with year 12, or as an original scheme as there is enough content there. A level physics notes download a full set of free revision notes for. Plum pudding model of the atom and rutherford and marsdens alpha experiments, being able to explain why the evidence from the scattering experiment led to a change in the atomic model. The internal resistance of a cell is simply the resistance from. The magnetic field b b size 12b is into the page, perpendicular to the moving rod and rails and, hence, to the area enclosed by them. The negative intercept on the yaxis is the internal resistance. Notes, flashcards, videos and past exam questions by topic for aqa physics. The hydrogen atoms are reduced by the halfreaction. Emf is the amount of energy of any form that is changed into electrical energy per coulomb of charge. One terminal of the device becomes positively charged, the other becomes negatively. Physics igcse 2012 exam revision notes by samuel lees and adrian guillot 1.
The emf induced is equal to the rate of change of magnetic flux linkage or the rate of flux cutting examplefor a conductor cutting lines of flux a. Those who will miss out on their results are advised to. I ee i i ii 2 2 rr the power delivered to the external circuit is equal to the power developed in the emf less the power lost through internal resistance. For a given device, if a charge q passes through that device, and gains an energy u, the net emf for that device is the energy gained per unit charge, or uq.
The emf is the potential difference produced by a device when no current is drawn from it. Electromotive force, emf, is a measure of the voltage that can be provided by a source. Cell, battery a combination of cells, solar cell, generator, dynamo, thermocouple. An emf is a force per unit charge line integrated along a path. The magnetic field is into the page, perpendicular to the moving rod and rails and, hence, to the area enclosed by them. Let us consider any arbitrary charge q in the conductor pq. Motional emf and induced electric fields are 100% totally different phenomena. The comprehensive resource you need to deliver or revise edexcel alevel physics electric and magnetic fields a2 year 2 unit 3. Emfs are voltages, which push do work on electrons from the high. In a circuit, electromotive force is the energy per unit charge converted from the other forms of energy into electrical energy to move the charge across the whole. The electromotive force emf of a source of electric potential energy is defined as the amount of electric energy per coulomb of positive charge as the cha rge passes. A level physics revision guide by richard woodside get your best grades with this examfocused text that will guide you through the content and skills you need to prepare for the big day.
It is visual and easy to comprehend with cloze passages and word banks lots of pictures and colour. When a conductor such as a metal wire is moved through a magnetic field. Electromotive force cie igcse physics revision notes. Electromotive force, abbreviation e or emf, energy per unit electric charge that is imparted by an energy source, such as an electric generator or a battery. This concept of motional emf can be explained with the help of the concept of lorentz force acting on free charge carriers of the conductor. Energy is converted from one form to another in the generator or battery as the device does work on the electric charge being transferred within itself. Since the flux is increasing, the induced field is in the.
A powerpoint to provide a general lesson structure and explanations. Back emf is the generator output of a motor, and so it is proportional to the motors angular velocity. A voltage is only an emf if it is a source of energy. Electromotive force emf is an unfamiliar concept to most people, but its closely linked to the more familiar concept of voltage. Candidates who would want their papers remarked should request for the same within a month after release of the results. Also, check out our other helpful revision resources for igcse physics 0625. Higher physics two questions question on internal resistance. A cell of emf and internal resistance r is connected in series to a resistor of resistance r as shown. Free igcse physics revision notes that will help you in revising for your exams. It is equal to the potential difference across the terminals of the cell when no current is flowing. Free physics revision notes on the topic electromotive force.
It can also be thought of as the energy converted into electrical energy, when 1 coulomb of charge passes through it. The number of turns or loops of the conductor in the field. Year 9 aqa gcse physics revision booklet atomic structure and radioactivity models of the atom know. We have seen an example of this in the situation where a moving magnet induces an emf in a stationary coil. Calculate the average magnitude of the induced emf if the change in shape occurs in 4.
The battery produces an electric field and this field accelerates the electrons in the opposite direction of. This resource is a lesson designed to continue the a level physics topic of electricity, following on with this lesson on emf and internal resistance. An activity based on calculating emf in a variety of circumstances. But inside the battery work has to be done to bring the positive charge from lower potential. A couple of the sheets have been differentiated down for students with downs syndrome. Break the redox reaction into reduction and oxidation halfreactions. A potential difference is developed across its ends. The power supply is said to have an electromotive force, or emf.
Today, emf is just another name for electrical potential energy, measured in units of energy power u. An emf induced by motion relative to a magnetic field is called a motional emf. Alevel physicsforces, fields and energyelectromagnetic. Higher physics homework unit 2 electricity exercise 7 ac, current, voltage, power and resistance exercise 8 emf and internal resistance exercise 9 capacitance exercise 10 electrons at work. The natural world, including your body, produces electromagnetic fields. Detailed notes with clear explanations, and examples. Emf induced in rod traveling through magnetic field video. Currentor positive charge flows from higher potential to lower potential across the resistance by itself. What is emerging in these observations is a connection. If you appreciate the help, consider tipping me to keep me going. As the rod moves with a constant speed v, the charge is also moving with.
Higher physics summary notes unit 1 our dynamic universe. For a conductor in a changing magnetic field, the factors affecting the size of the induced emf are. Written by expert teachers for the cie igcse 91 0972 ag 0625 syllabus. Internal resistance, emf and potential difference scool. A crash course in particle physics cox part 1 hubble and red shift part 2.
Past papers, exam questions by topic, revision notes, worksheets and solution banks. Back emf is the generator output of a motor, and so it is proportional to the motors angular velocity it is zero when the motor is first turned on, meaning that the coil receives the full driving voltage and the motor draws maximum current when it is on but not turning. This is represented by the equation emf lvb, where l is length of the object moving. A full set of revision notes free to help aas physics students. A resistor r1 is connected in series with a parallel connection of resistors r2 and r3. Electromotive force spm physics form 4form 5 revision notes. The emf electromotive force is the the potential difference between the terminals of a battery when no current is flowing through an external circuit when the circuit is open. Pdf download allen jee mains 2020 minor and major test papers with solutions apr 12, 2020. Energy released when nucleons are assembled into nucleus. Which means that all emf are voltages but not all voltages are emf.
Electromotive force and internal resistance physics. It is zero when the motor is first turned on, meaning that the coil receives the full driving voltage and the motor draws maximum current when it is on but not turning. To find the emf and internal resistance of a cell, the following circuit is set up. The electromagnetic field interacts with the magnetic field of the surrounding. How to develop effective study habits mar, 2020 pdf view jh sir physical chemistry notes for class 12 mar 8, 2020 pdf nv sir 11th class physics notes for jee and boards feb 27, 2020 pdf download nv sir physics notes complete for jee feb 22, 2020.
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