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Performance-Based Assessments for Basic Electricity Competencies
29 questions By Tony R. Kuphaldt
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Question 16 of 29
Reveal answerUse circuit simulation software to verify your predicted and measured parameter values.
Notes:You will need to provide some low-resistance specimens for your students to measure using this technique. Motor armature coils work well for this purpose, as do large power resistors with the labels scratched off.
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Question 17 of 29
Reveal answerMeasure the wire length to check your calculation!
Notes:You will need to provide some spools of wire for your students to measure using this technique. Your students will need to find wire tables correlating length with resistance (at different temperatures, if the room temperature is significantly different from the standard temperature given in the table).
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Question 18 of 29
Reveal answerI won’t reveal the answer here as to what effect magnitude has on magnetic field strength, but I will suggest a way to test for strength: place the compass at a distance from the coil, where the coil’s field has a relatively small effect on the needle position in relation to the ambient magnetic field.
Notes:Old solenoid valve coils work very well for this exercise, as do spools of wire with large steel bolts passed through the center. Students may also wind their own coils using small-gauge magnet wire and a steel bolt. If the coils are hollow, you may experiment with and without ferrous cores, to demonstrate the effects of a ferromagnetic flux path on the field strength produced.
