A 12-gauge (diameter 2.05 mm) copper wire has a total resistance of Ω. If the resistivity of copper is

(5 pts) What is the charge on ? In class we would have called this .

(4 pts) A capacitor with a capacitance of μF and a resistance of Ω is connected in series to the terminals of a battery with an EMF of V (negligible internal resistance) and a switch that has been open for a long time. At time , the switch is closed to leave a charging RC circuit. In the following problems, we will try to find some information at time and at time = ms. What is the time constant

(2 pts) We have the circuit shown here… In this figure, some currents, EMF sources, and resistors take the following values = 1.00 A,  = .00 V,  = .00 V,  = .00 Ω,  = .00 Ω,  = .00 Ω, and  = .00 Ω. The currents are positive if in the direction indicated. The unknown is positive if the polarity is as illustrated here. Negative values are fine, they just indicate that the pictured current is the wrong way or the pictured EMF has a different polarity. You won’t calculate this initially, but give your value for here in units of mA. Be sure to include the sign if appropriate.

(5 pts) What is your value for ? Be sure to include sign if appropriate.

(3 pts) Shown here is a capacitor array connected to an EMF source . The capacitors have the values  = μF, = μF, = μF, = μF, and = μF. A voltmeter is measuring the potential at point with respect to point to be = V. What is the equivalent capacitance between point and point in units of μF?

What is the equivalent resistance between points A and B in the figure when =  Ω? Please enter your answer in Ω.

How long will it take a charged 80 μF capacitor to lose 20% of its initial energy when it is allowed to discharge through a 45 Ω resistor?

(3 pts) You now have 3 equations for 3 unknowns (, , and ). You now need to solve. You have already entered your value for above. Give some details for how you found this value here.

Two cables of the same length are made of the same material, except that one cable has twice the diameter of the other cable. When the same potential difference is maintained across both cables, which of the following statements are true? (There may be more than one correct choice.)