If R = 3.0 kΩ,C = 5.0 mF,ε = 6.0 V,Q = 15 mC,and I = 4.0 mA,what is the potential difference V_b − V_a? A)−3.0 V B)+9.0 V C)−15 V D)+21 V E)−6.0 V

Question

Quizplus · Accepted Answer

The potential difference across the capacitor can be found using the formula: ΔV = Q/C = (15 mC)/(5.0 mF) = 3.0 V The potential difference across the resistor can be found using Ohm's Law: ΔV = IR = (4.0 mA)(3.0 kΩ) = 12 V Therefore, the potential difference V_b − V_a is equal to: ΔV = (12 V) - (3.0 V) = 9.0 V However, the question asks for the sign of the potential difference. Since the potential difference across the resistor is greater than the potential difference across the capacitor, the current will flow from V_b to V_a. This means that the sign of the potential difference will be negative, so the correct answer is: A) −3.0 V

If R = 30 KΩ,C = 5