A battery supplies a constant current of I = 15 mA to the circuit of a flashlight with a resistance of R = 4.1 kΩ.   a.) Input an expression for the potential difference across the terminals of the battery, ΔV.  b.) What is this potential difference in volts?  c.) Keeping the resistance the same, if the flashlight battery has a potential difference of ΔV = 7.5 V, how much current flows through the circuit, in amperes?

b. A capacitor in a RC circuit is charged for a long time as shown in the Figure below, where the battery voltage V=6V. The switch s is flipped from a to b and the capacitor discharges through the R = 4 MQ resistor. 4 seconds after the switch is flipped to discharge the capacitor, the voltage across the capacitor is 3 V. What are (a) The time constant of this circuit (b) The capacitance of the capacitor (c) The current in the circuit and the charge on the capacitor just before the switch is flipped from a to b. (d) The current in the circuit immediately after the switch is flipped from a to b

In the figure, each resistance is R=1 and the voltage of the battery is 1.3 V. d) What is the power input of the resistor which is connected between points A and B, in watt (W). R www R B R A www C R www R

A parallel plat capacitor is being charged by a battery of Ɛ = 12 V. If the total resistance of the circuit is 5.0 k2, and if the time constant for this circuit is 7= 95 ms (milliseconds), then: 1. What is the capacitance, C, of the capacitor? а) b) What is electric charge on the capacitor (as a function of time)? c) What is the current in the circuit (as a function of time)? d) If the capacitor plates are circular and the separation distance is d = 0.8 mm, calculate the E field value between the plates of the capacitor (as a function of time). e) Calculate the B field value and directions, between the plates of the capacitor (as a function of time), at a distance r from the center of plates.