Provide evidence for the "domain theory" of magnetism.
What will be an ideal response?
Evidence of this "domain theory" is that if a magnet is heated, or hit repeatedly with a hammer, it loses its magnetism (the domains are jarred back into a random arrangement). Also, if an artificial magnet is left by itself, it slowly loses its magnetism. To prevent this loss, bar magnets should be stacked on top of each other with opposite poles together; keeper bars should be placed across horseshoe magnets. Both methods maintain the magnetic field.
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Choose one of the products from the list below and note key features and functions for the product as produced today. Then, go back one generation (18–25 years) to family, relatives, or friends and ask them to describe the key features and functions of the same product as produced at that time. Note changes and improvements and prepare a brief report.
(a) bicycle (b) electric coffeemaker (c) color television (d) landline telephone (e) cookware (pots, pans, skillets) (f) vacuum cleaner (g) microwave oven
What is a board foot? Cubic foot? Cord?
What will be an ideal response?
Calculate the electrical pressure required to flow 6 amps through a 2 ohm resistance
A. 3 volts B. .33 volts C. 6 volts D. 12 volts
In a motor that has a rotating magnetic field, the speed of that magnetic field is referred to as the _____.
A. rotor speed B. stator speed C. synchronous speed D. slip speed