Question

A resistor was connected to a variable voltage source and the current was measured for various voltages.The following results were obtained:

Trial	Voltage (V)	Current (mA)
1	1	3.3
2	1.96	7.1
3	3.03	10.9
4	3.98	13.7

where V is the voltage difference across the resistor and I is the current travelling through the resistor at the same time.

Calculate the resistance for each trial and the average of the resistances. Determine the uncertainty in the average resistance. Report these values below. (When entering units, use ohm for Ω.)

R = 286.9 ohm ± _____ ohm

This resistor is connected in series with an unknown capacitor.The potential difference across the capacitor is measured at various times while it is charged by a battery of 4.760 volts and the following results are recorded:

Voltage (V)	Time (s)
0.952	0.00357
1.925	0.00823
2.835	0.01443
3.808	0.02575

Use Excel to construct a spreadsheet that shows the above data as well as any and all calculations needed to compute the resistance of the circuit component in question. Create a graph of -ln[(V_final-V)/V_final] vs. the time.

Use Excel's trendline to plot a best-fit line through the data. Use the LINEST function in Excel to determine the slope and intercept with corresponding uncertainties. Report these values below.

Slope = _____ ± ______ 1/s

Capacitance = ______ ± ______ microfarads

Answer 1