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Electromotive Force and Potential Difference. Emf and P.d. You should be able to: (a) define potential difference ( p.d .); (b) select and use the equation W = VQ ; (c) define the volt ; (d) describe how a voltmeter may be used to determine the p.d . across a component;
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Emf and P.d You should be able to: (a) define potential difference (p.d.); (b) select and use the equation W = VQ; (c) define the volt; (d) describe how a voltmeter may be used to determine the p.d. across a component; (e) define electromotive force (e.m.f.) of a source such as a cell or a power supply; (f) describe the difference between e.m.f. and p.d in terms of energy transfer
Circuit Symbols • Draw any circuit symbol that you can remember. ( there are 16 that you need to know)
Emf and P.d Emf and Potential difference are about energy
Electromotive force is the energy transferred per coulomb when one other type of energy is converted into electrical energy. Emf and P.d • This tells us that emf: • Is measured in joules per coulomb • That it always deals with the supply of electrical energy.
Potential difference is the electrical energy transferred per coulomb when electrical energy is converted into another form of energy. Emf and P.d • This tells us that pd: • Is measured in joules per coulomb • That it always deals with the use of electrical energy.
Emf and P.d V = W Q
12V Emf and P.d Describe in terms of energy what is happening in this circuit. 3V 9V