Magnetism Science Chap

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Q1 flip Name ways to make an electric motor more powerful by making its magnet stronger?

flip A1 These are a few ways to make an electric motor more powerful: Use a larger current flowing through the coil. Increase the number of turns of wire around the coil. Use a soft-iron core in the middle of the coil. Use stronger magnets, such as electromagnets either side of the coil.

flip Explain how the acronym: M y F ine C lothes Can be used to remember the left-hand rule that is used with motors?

flip 2 M y = Thu m b to remember M otion of wire F ine = F irst finger to remember F ield C lothes = S econd finger to remember C urrent Place fingers at 90 degrees from each other.

flip Apply the left-hand rule to the following drawing. Where does your thumb, first and second fingers point to?

flip 3 C urrent = Se c ond finger points in direction of current F ield = F irst finger points in direction of field (North to South) M otion = Thu m b points up so wire moves upwards.

flip When a current flows through a wire it produces a: (finish the sentence)

flip 4 When a current flows through a wire it produces a magnetic field. Red wire is positive so it is the north pole. Do you notice that the compasses point away from the north?

flip The simplest type of electromagnet is a coiled piece of wire. A coil forming the shape of a straight tube (similar to a corkscrew). What is this type of electromagnet called?

flip 5 It is called a solenoid. The current of negative flows to the positive. The north pole will be positive.

flip In the two following diagrams of cobalt. Explain which will be magnetic and what term is used to described the little rods that are part of atoms.

flip 6 In the case of the domains that are not organized, the cobalt will not be magnetic. In the case of the domains that are organized, the cobalt will be magnetic. They become organized if a magnet comes close to the piece of cobalt. A domain is the ordering of electron spins. When they are organized in the same spin then they create magnetism. unorganized organized

flip A B What terms are used to describe case A and case B

flip 7 A B Case A is: attraction Case B is: repulsion

flip Draw the representation of the direction of the magnetic field around the Earth.

flip 8 The red part in each compass indicated the north. The field travels from north toward the south. Therefore the geographical north is the magnetic south.

flip Use the two following pictures to explain the term ferromagnetic. Also state which three elements are known to be ferromagnetic.

flip 9 Iron, nickel, cobalt are some common elements that show a unique magnetic behavior which is called ferromagnetism. Ferromagnetic materials have their unpaired electron spins to line up parallel with each other in a region called a domain if externally imposed magnetic field, say from a solenoid. Domains can align causing magnetism. Ferromagnets will tend to stay magnetized to some extent after being subjected to an external magnetic field.

flip In the above left diagram, using the left-hand rule, what will be the direction of the current flow when the switch closes? Sometimes you meet two ideas of current: conventional current and electron current. Which current does the left-hand rule uses?

flip 10 The purple line indicates the current used with the left-hand rule.

flip _ Use the left-hand rule to indicate the current, the motion and the direction of the field.

flip 11 Remember that the electron flow is the current. The flow goes from north to south. The motion is upwards.

flip Use the left-hand rule to show the current, the motion and the field.

flip 12 Thu m b = motion ( in this case downward) F irst finger = field Se c ond finger = current

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The END (exit program) Paul Widergren ©