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What are we doing Today? Ch. 5 Magnetism Homework Questions Check Hand in Lab 41-42 Chapter 5 Notes In class questions & homework
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p. 174 Question 19 (b,c) textbook
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p. 174 Question 20 (a,b)
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Magnetism (Chapter 5 - p.163) Magnet – An object that can attract other objects containing iron, cobalt or nickel
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Magnetic Poles The strength of a magnet is concentrated at the ends, called north and south “poles” of the magnet. NS N E W S N Compass Bar magnet S N Iron filings
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If you cut a magnet in half, you get 2 magnets!
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Magnetism (Chapter 5 - p.163) Magnetic Field – Is the area of space in which the magnetic force of a magnet can act on another magnet.
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Magnetic Fields * Magnetic field lines move away from north poles and toward south poles.
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Magnetic Field Lines NS We can describe magnetic field lines by imagining a tiny compass placed at nearby points. The direction of the magnetic field B at any point is the same as the direction indicated by this compass.
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Field Lines Between Magnets NS NN Unlike poles Like poles Leave N and enter S Attraction Repulsion
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Ferromagnetic Substance (p.167) Ferromagnetic materials are materials that have magnetic properties similar to those of iron. They can become permanently magnetized. Examples of ferromagnetic materials are nickel and cobalt.
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ELECTROMAGNET Electromagnetism a moving charge (electricity) produces a magnetic field More coils of wire= more current = stronger magnet Bigger battery = stronger magnet A magnet with a field produced by an electric current
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Magnetic field pattern around a straight wire. The resulting magnetic field lines form concentric circles around the wire. The Right-Hand rule can be used to predict the direction of the magnetic field
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Magnetic field around a wire carrying current
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The Electromagnet By the Right Hand Rule, a coil of wire with current flowing in it will create a magnetic field The strength of the magnetic field depends on The amount of current in a wire – More current means stronger magnetic field The number of turns in the coil – More turns means stronger magnetic field The material in the coil – Magnetic materials like iron and steel make the magnetic field stronger
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The Electromagnet A simple electromagnet can be made by coiling some wire around a steel nail, and connecting a battery to it. As current rotates around the nail, a magnetic field is created with the North pole at the bottom and the South pole at the top
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The Electromagnet Electromagnets are found in many everyday objects such as – Motors and generators – Doorbells – Speakers – Hard drives – VHS and Audio cassette tapes – Telephones
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Solenoid (p.169) EST Solenoid: Is a cylindrical coil of live wire.
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Magnetic Field of a Solenoid(EST) Look at p.169 in your textbook
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Classwork P. 174 Questions 21-25
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Exit Question(s) Draw the following circuits and which of the circuits below are connected in series, and which are connected in parallel?
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Number 1 Answer: Parallel
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Number 2 Answer: Series
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Number 3 Answer: Parallel
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Number 4 Answer: Series
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The circuit is composed of a 6.0-V battery connected to a 10-Ω resistor. It includes an ammeter and a voltmeter connected to the resistor terminals.(look up in chapter 5 on diagrams of circuits). a)Draw the circuit diagram, including the measuring instruments.
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Exit Questions 1) The potential difference in a circuit is determined to be 10 volts. If the resistance is 5 ohms, what must the current intensity be?
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The potential difference in a circuit is determined to be 10 volts. If the resistance is 5 ohms, what must the current intensity be? Answer: 1.Determine what you are looking for. 2.List what you know and don’t know. V = 10 Volts R = 5 ohms I = ? 3. Use equation V = R x I Solve for I, so I = V/R 4. I = 10 Volts / 5 ohms = 2 A Answer: The current intensity will be 2 A (Amps)
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What To Do Now?
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