* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Le magnétisme et l`électromagnétisme
Magnetosphere of Jupiter wikipedia , lookup
Electromotive force wikipedia , lookup
Geomagnetic storm wikipedia , lookup
Maxwell's equations wikipedia , lookup
Magnetosphere of Saturn wikipedia , lookup
Skin effect wikipedia , lookup
Friction-plate electromagnetic couplings wikipedia , lookup
Edward Sabine wikipedia , lookup
Mathematical descriptions of the electromagnetic field wikipedia , lookup
Magnetic stripe card wikipedia , lookup
Neutron magnetic moment wikipedia , lookup
Lorentz force wikipedia , lookup
Magnetometer wikipedia , lookup
Magnetic field wikipedia , lookup
Magnetic nanoparticles wikipedia , lookup
Magnetic monopole wikipedia , lookup
Giant magnetoresistance wikipedia , lookup
Earth's magnetic field wikipedia , lookup
Electromagnetic field wikipedia , lookup
Magnetotactic bacteria wikipedia , lookup
Electromagnetism wikipedia , lookup
Magnetotellurics wikipedia , lookup
Magnetoreception wikipedia , lookup
Magnetohydrodynamics wikipedia , lookup
Multiferroics wikipedia , lookup
Magnetochemistry wikipedia , lookup
Superconducting magnet wikipedia , lookup
Electromagnet wikipedia , lookup
Force between magnets wikipedia , lookup
Name: ____________________________________________ Group: __________ Support activities – Second Year of Secondary Cycle Two ACTIVITY 23 ANSWER KEY Date: __________________ AST STUDENT BOOK: Chapter 5, pages 163–171 RELATED HANDOUT: Concept review 23 Magnetism and electromagnetism 1. Complete the following sentences, using the words or groups of words in the box below. You may use some words more than once. • • • • • • • • • • • • • • adding aligned artificial attract each other attraction circular cobalt coming out of conserve direction distance domains dynamic electrical • electromagnet(s) • electromagnetic induction • electromagnetism • entering into • ferromagnetic • ferromagnetic core • fingers • generators • geographic North Pole • increasing • intensity • like • magnet • magnetic field • magnetic field lines • magnetism • magnetized • mechanical • more powerful • motion • moving • natural • nickel • not aligned • opposite • • • • • • • • • • • • • ore permanent powerful right-hand rule rolled sharp blow solenoid south-seeking speed steel stopping temporary thumb © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. Magnetism a) ________________________ describes all the phenomena caused by magnets. Magnets nickel are objects that can attract other objects containing iron, ________________________ or ore cobalt. Around 600 BCE, the Greeks discovered an ________________________ called natural magnetite, which is a ________________________ magnet with this property. b) Certain metals have magnetic properties, which can be explained by their composition: they domains contain a set of regions called “________________________ ,” and each of these regions not aligned acts like a tiny magnet. The directions of these domains are ________________________ if magnetized the metal is not magnetized. If the metal is ________________________ , its domains will aligned be well ________________________ . The greater the number of aligned domains, the more powerful ________________________ the magnet. Observatory / Guide 11129-B 1 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 23 Magnetism and electromagnetism Name: ____________________________________________ Group: __________ Date: __________________ south-seeking c) Each magnet has a north-seeking and a ________________________ pole. By convention, the north pole of a magnet corresponds to the end that naturally turns toward the magnetic geographic North Pole pole that is located close to the Earth’s ________________________ . attraction d) Magnets interact with one another through forces of ________________________ and attract each other repulsion. In other words, opposite magnetic poles ________________________ and like ________________________ magnetic poles repel each other. These forces can act distance across a ________________________ . In a diagram of a magnetic field, they are magnetic field lines represented by ________________________. By convention, the lines are drawn coming out of entering into ________________________ the north pole and ________________________ the south pole of a magnet. cobalt e) Iron, nickel and ________________________ can be used to make artificial ________________________ magnets. To do so, they are exposed to the magnetic field ________________________ of another magnet. Substances with the ability to become ferromagnetic magnets are described as “________________________ .” They can be demagnetized if, sharp blow for example, they receive a ________________________ or are placed in a magnetic field of opposite polarity. f) Magnetic remanence is the ability of a material to acquire and conserve ________________________ its magnetic properties. There are two types of magnets: temporary ________________________ magnets, which have low magnetic remanence and readily © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. acquire and lose their magnetic properties (for example, iron containing few impurities), and permanent ________________________ magnets, which have high magnetic remanence and are hard steel to magnetize and demagnetize (for example, ________________________ ). g) Electricity can be used to make magnets. The interaction between magnetism and electromagnetism electricity is called “________________________ .” An electric current can generate a opposite magnetic field, and the ________________________ is also true. Only dynamic ________________________ electricity can generate a magnetic field because the motion electrical charges must be in ________________________. right-hand rule h) Using the ________________________ , we can determine the direction of the magnetic thumb field lines of a live wire. The ________________________ points in the direction of the current, from the positive terminal toward the negative terminal. The fingers ________________________ wrapped around the wire show the direction of the magnetic circular field lines. These lines are ________________________ . Observatory / Guide 11129-B 2 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 23 Magnetism and electromagnetism Name: ____________________________________________ Group: __________ Date: __________________ i) To increase the intensity of the magnetic field of a live wire, it can be rolled ________________________ into a coil of regularly shaped loops to form a magnetic field solenoid ________________________ . This formation will have a ________________________ that resembles that of a bar magnet. However, three characteristics distinguish one from the solenoid other: The magnetic field of a ________________________ can be switched on or off stopping simply by ________________________ the current flow. It is possible to change the direction ________________________ of its magnetic field lines by reversing the current direction. increasing Finally, the intensity of its magnetic field can be increased by ________________________ the number of loops or by increasing current intensity. electromagnet j) A solenoid can be transformed into an ________________________ by adding a ferromagnetic core ________________________ inside the coil. The magnetic field is produced by both the ferromagnetic core solenoid and the ________________________ . The resulting magnet is very Electromagnets powerful ________________________ . ________________________ have the same advantages as adding solenoids, but their magnetism is increased by ________________________ the ferromagnetic core. They are widely used in the field of electricity, notably to transform mechanical electrical energy into ________________________ energy. k) An electric current can be generated from a magnetic field by electromagnetic induction . To do this, an electric current is generated in a ________________________ conductor by varying a magnetic field around the conductor. The magnetic field must be © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. moving ________________________ in relation to the conductor. This can be done by moving ________________________ a conductor inside a magnetic field or by moving a magnet ________________________ around a conductor. intensity l) Electromagnetic induction is affected by the ________________________ of the magnetic speed field and the ________________________ at which it moves in relation to the conductor. Electromagnetic induction is widely used to transform mechanical energy into electrical ________________________ energy, for example in the turbines and generators ________________________ in the dams of hydroelectric plants. Observatory / Guide 11129-B 3 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 23 Magnetism and electromagnetism Name: ____________________________________________ Group: __________ Date: __________________ 2. The figure below represents the Earth, which is a large magnet. Complete the figure with the following terms. – geographic North Pole – North Magnetic Pole – geographic South Pole – South Magnetic Pole Geographic North Pole South Magnetic Pole North Magnetic Pole Geographic South Pole 3. The circles below represent compasses. In each situation, draw the needles of the compasses, using an arrow to show the direction they point. b) © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. a) 4. Draw the magnetic field of each of the magnets below. b) a) Observatory / Guide 11129-B 4 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 23 Magnetism and electromagnetism Name: ____________________________________________ Group: __________ Date: __________________ 5. Draw the magnetic field lines for each of the solenoids below. a) © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. b) Observatory / Guide 11129-B 5 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 23 Magnetism and electromagnetism