Conceptual Physics I, Day 13
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What kind of force does a magnetic field exert on a charge? on a current in a wire? on charges in a wire when the wire is moved through the magnetic field? How is electric voltage generated in an electric generator? How is the force which turns an electric motor produced? What useful tasks can be accomplished by a transformer? What are the limitations on the power output of a transformer? How can the ignition coil of an automobile generate the very high voltages to fire the spark plugs from just a 12 volt battery? We talk of point charges as sources of electric field. Is there such a thing as a point magnetic source? Describe the magnetic field from a bar magnet and an electromagnet. Why does the presence of an iron core make an electromagnet much stronger? Why is a hand-cranked generator harder to turn if we are using it to light bulb compared to an unconnected generator? What is the difference between a motor and a generator? Why is your refrigerator most likely to kick out the circuit breaker when it first turns on? Why is the starting current for a motor so much higher than the current when it is running continuously? Describe the basic process of generating electricity at a typical electric power plant. Why are transformers used at the power plant to raise the voltage to very high voltages for transmission cross-country? A voltmeter must be used in parallel with the circuit being measured and the ammeter in series. Describe why and describe the consequences when these conditions are not met. What causes the needle in a moving coil meter to move? The same meter movement can be used in an instrument to measure voltage, current, or resistance by just changing switch positions. Describe how the meter is changed to make each. |
*Magnetic force *Magnetic field *Magnetic field of the Earth *Generator *Faraday's Law *Electric Motor *Transformer *Ignition coil *Bar Magnet *Electromagnet *Magnetic Field of a Current *Magnetic field of Current Loop *Solenoid *Magnet and Coil *Motional Voltage *Voltmeter *Ammeter *Voltmeter design *Ammeter design |