20A
YOUR ANSWER:
The two types of resistors are axial-lead and nonmetallic.
(From P1-17A)
Shame. An axial-lead resistor is an example of a nonmetallic type of resistor. Also, a wire-wound
resistor is an example of a metallic type of resistor. Go back to Page 1-17A and choose the correct answer.
20B
YOUR ANSWER:
False.
(From P1-16A)
Good. You are still on the right track. Now let's go back and consider the five factors that determine the
choice of a conductor. We'll take them one at a time. First, we'll talk about cost. That item pretty well explains
itself. Silver is the best metallic conductor there is, but just imagine the cost of a normal everyday radio if it had
200 feet of silver wire inside of it. However, let's look at copper. It's almost as good a conductor as silver, and
the cost is only a fraction as much. OK, so much for cost. The next of our five considerations was the ability to
be fused. In the construction of electronic gear and electrical appliances, there are thousands of places where the
conductors have to be joined together. The standard way of joining these conductors together is by soldering.
Therefore, for ease of construction and maintenance, the material would have to be easily soldered. Copper is
very easy to solder.
The next of our five items was the melting point. Here, again, we would have to consider the place where
we were going to use the conductor. If we wanted a fuse, we would use a material that had a low melting point.
If we were making a light bulb filament or an element for an electric toaster, we would want a material with a
high melting point.
Complete the following statement:
Of the five factors determining the choice of a conductor, the three we have talked about so far are
cost, temperature and melting point.
Page 1-11B
melting point, cost, and the ability to
be fused.
Page 1-12B
ability to be fused, cost, and the length.
Page 1-23A
IT0340
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