Let’s Review…
You’ve already learned a lot in this section. It’s time to apply this information to some problem solving. First, take a look at the vocabulary review so you know you are ready to take on those terms in the problems. Then, move on from there for an example and some self-check problems.
Vocabulary Self Check
Now, you try. Match the following terms with the proper definitions before moving on to your problem solving.
Tutorial: Using Coulomb’s Law
In this example, you will see how to use Coulomb’s Law to solve a problem. Select the play button to begin the tutorial, and then use the navigation buttons to pause/stop, continue, or reset the tutorial. View the presentation as often as you would like, and take notes as you follow along. Be sure to set your volume at a reasonable level before you begin.
More Problems Self Check
Now, you try. Complete the self-check activity by looking at the questions below, working them out, and then clicking on the question to review the solution.
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A hair dryer draws 7.5 A when plugged into a 120-V line. (a) What is its resistance? (b) How much charge passes through it in 15 min? (Assume direct current.)
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An electric device draws 6.50 A at 240 V. (a) If the voltage drops by 15%, what will be the current, assuming nothing else changes? (b) If the resistance of the device were reduced by 15%, what current would be drawn at 240 V?
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, the current will also drop by 15%.
, the current must be divided by 0.85.
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A 12-V battery causes a current of 0.60 A through a resistor. (a) What is its resistance, and (b) how many joules of energy does the battery lose in a minute?
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loses a potential energy of 
as it passes through the resistor. The amount of charge is found by:
