Problem:
1. A) First describe the magnetic field that will be generated when the current is flowing (switch would be closed) in the apparatus shown above (simple solenoid). You can label this on the image, but you must also explain how it is generated and how you would find the direction of the field.
B) Then explain how Lenz's law can be used to predict the direction of an induced current when the switch is turned off (opened) and then back on (closed).
Answer:
2. A transformer has 300,000 windings in its primary coil and uses 10,000V AC input.
A) How many windings would be needed to produce at output of 120V AC? Is this a step down or step up transformer?
B) Explain why a transformer only works with AC and not DC currents.
3. a) Compare and contrast magnetic and electric fields. Your answer should include at least 2 ways they are similar and 2 ways that they differ.
b) Include a diagram of an electric field for either a positive or negative point charge and a diagram for a typical bar magnet. Make sure you show the field lines (including direction) and label the charges and poles.
Answer: