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3) On the spreadsheet calculate R =
V/i for each data point and plot V vs. i, and R vs.
i.
4) Save the graphs and note the values
of the highest and lowest values of resistance calculated.
5) Now, substitute
the gray rectangular resistor in place of the light
bulb in the circuit, and repeat steps 1, 2, 3, and 4.
6) If a graph of V vs. i is a straight
line, what quantity does the slope of the line represent?
7) Did either of the graphs of V vs.
i result in a straight line? If so, which one.
8) Did either the light bulb or the
resistor obey Ohm's law? If so, which one(s)?
II. Now you will see how the resistance
of different resistors varies with temperature.
9) Attach the brown cylindrical resistor
with the colored bands to the multimeter. Set the multimeter
to measure resistance and to display as many significant
figures as is possible. Record the resistance.
10) Put the resistor into a cup of
liquid nitrogen, and wait till it stops boiling. Record
the resistance.
11) When the resistor was placed in
liquid nitrogen,
12) When the resistor was placed in
liquid nitrogen, did its resistance increase, decrease,
or remain the same?
13) Replace the resistor with the hollow
brown cylindrical resistor, and repeat steps 9 through
12.
14) What general type of material (conductor,
semiconductor, insulator) might each of the two resistors
be made of? (Hint: consult the table on page 619 of
your text book).
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