QUESTIONS (Don’t forget to show all your work!)
Click in the links below to go directly to a particular week.
Week 5 - Ohm's Law (Pasco)
Compare the slope of the 10-ohm resistor as shown in the Scope to the "official" value of resistance. In other words, how close is the value of the slope to the value of the resistance?
The slope of the voltage to current is close to the rated value of the resistors.
Why does the slope of the bulb trace change?
When the light bulb filament becomes warm enough to glow, its resistance changes. This causes the current to change relative to the amount of voltage.
Does the resistor have a constant resistance? Does the light bulb? Why or why not?
The resistors appear to have a constant resistance. The light bulb filament does not have a constant resistance, at least at low frequencies.
The slope of the graph for the light bulb is not symmetric. Why is the slope of the current trace different when the filament is heating up compared to the trace of current when the filament is cooling down?
The rate at which the filament heats up is not the same as the rate at which it cools down. As the filament heats up, so do the gasses inside the bulb. They do not have the same specific heat as the filament.
There are no assigned questions for this experiment!
However, if you would like to get some extra credit points, you can choose two problems from your lecture textbook on simple circuits, (only containing batteries & resistors):
1) Resistors in series & 2) Resistors in parallel.
NOTE: In order to obtain the extra credit points, worth 0.1 standard deviations added to your final score, both problems must be completely correct. NO PARTIAL CREDIT!
Does the insertion of additional resistance in a series circuit materially affect the difference of potential across the entire group?
Some types of Christmas tree lights consist of about eight lights connected in series. If one bulb burns out, and the connection is completed around the empty socket so that the remaining seven lights will "burn," what happens to the voltage (PD) across the individual lights? Explain.