Your 'the rc circuit' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Your comment or question: **
** Initial voltage and resistance, table of voltage vs. clock time: **
** Times to fall from 4 v to 2 v; 3 v to 1.5 v; 2 v to 1 v; 1 v to .5 v, based on graph. **
** Table of current vs. clock time using same resistor as before, again starting with 4 volts +- .02 volts. **
** Times to fall from initial current to half; 75% to half this; 50% to half this; 25% to half this, based on graph. **
** Within experimental uncertainty, are the times you reported above the same?; Are they the same as the times you reports for voltages to drop from 4 v to 2 v, 3 v to 1.5 v, etc?; Is there any pattern here? **
** Table of voltage, current and resistance vs. clock time: **
** Slope and vertical intercept of R vs. I graph; units of your slope and vertical intercept; equation of your straight line. **
** Report for the 'other' resistor:; Resistance; half-life; explanation of half-life; equation of R vs. I; complete report. **
** Number of times you had to reverse the cranking before you first saw a negative voltage, with 6.3 V .15 A bulb; descriptions. **
** When the voltage was changing most quickly, was the bulb at it brightest, at its dimmest, or somewhere in between? **
** Number of times you had to reverse the cranking before you first saw a negative voltage, with 33 ohm resistor; descriptions. **
** How many 'beeps', and how many seconds, were required to return to 0 voltage after reversal;; was voltage changing more quickly as you approached the 'peak' voltage or as you approached 0 voltage; 'peak' voltage. **
7 beeps, 4.67 seconds
The voltage was changing more quickly as I approached 0.
Peak voltage was 4 V.
** Voltage at 1.5 cranks per second. **
4 V
** Values of t / (RC), e^(-; t / (RC) ), 1 - e^(- t / (RC)) and V_source * (1 - e^(- t / (RC) ). **
2.02, .1326, .8674, 3.469
I'm not sure this is correct because that would mean that the voltage at 100 beeps; which I thought was 4 V was in fact 3.469V. Which either means my math is wrong or that I miss counted my beeps, which is possible, or the meter is not exact.
** Your reported value of V(t) = V_source * (1 - e^(- t / (RC) ) and of the voltage observed after 100 'cranks'; difference between your observations and the value of V(t) as a percent of the value of V(t): **
3.469 V, 4V
15.3 %
** According to the function V(t) = V_source * (1 - e^(- t / (RC) ), what should be the voltages after 25, 50 and 75 'beeps'? **
25 beeps = 1.58 V
50 beeps = 2.54 V
75 beeps = 3.12 V
** Values of reversed voltage, V_previous and V1_0, t; value of V1(t). **
-4V, 4V, -4V, 4 seconds
3.54 V
** How many Coulombs does the capacitor store at 4 volts? **
Q = C *V
Q = 1 C/V (4V)
Q = 4 C
The capacitor is a 1 F capacitor which means it is 1 C/V so at 4 V is is 4 C.
** How many Coulombs does the capacitor contain at 3.5 volts?; How many Coulombs does it therefore lose between 4 volts and 3.5 volts?; **
3.5 C, .5 C
Since the capacitor is a constant 1 F then it will have 3.5 C (1 C/V * 3.5 V) so the difference between 4 C and 3.5 C is .5 C or .5C lost.
** According to your data, how long did it take for this to occur when the flow was through a 33-ohm resistor?; On the average how many Coulombs therefore flowed per second as the capacitor discharged from 4 V to 3.5 V? **
1V/s, .5 seconds
It took 6 beeps or 4 seconds to discharge 4 volts through a 33 ohm resistance so that is 1 volt per second. To discharge .5V it would take .5 seconds.
** According to your data, what was the average current as the voltage dropped from 4 V to 3.5 V?; How does this compare with the preceding result, how should it compare and why? **
It compares reasonably closely on my graph. The slope was very steep at that point in the both graphs. However my scale is not perfect and is larger than I would like to confidently state they are the same.
** How long did it take you to complete the experiment? **
30 minutes
** **
This is the rest of the assignment I submitted on July 10th
Good work on this experiment. Let me know if you have any questions.