\f1 An initially uncharged 3.65 x 106 F capacitor and a 8090 Q resistor are connected in series to a 1.50 V battery that has negligible internal resistance. What is the initial current I9 in the circuit? Calculate the circuit's time constant '3. How much time 1' must elapse from the closing of the circuit for the current to decrease to 2.69% of its initial value? I = S A heart defibrillator being used on a patient has an RC time constant of 15.0 ms due to the resistance of the patient and the capacitance of the defibrillator. If the defibrillator has an 7.75 #F capacitance, what is the resistance of the path through the patient? resistance: If the initial voltage is 12.0 k V, how long does it take to decline to 323 V? time: S Question Credit: OpenStax College PhysicsCell membranes contain channels that allow K+ ions to leak out. Consider a channel that has a diameter of 1.65 nm and a length of 11.5 am. If the channel has a resistance of 19.5 (19, what is the resistivity p of the solution in the channel? A circuit contains four resistors. Resistor R1 has a resistance of 51.0 (2, resistor R; has a resistance of 129 .Q, resistor R3 has a resistance of 87.0 $1, and resistor R4 has a resistance of 163 Q. If the battery has a voltage of V = 45.0 V, how much power is dissipated in each resistor? Two resistors, R. = 2.5? Q and R2 = 6.41 9., are connected in series to a battery with an EMF of 24.0 V and negligible internal resistance. Find the current I I through R] and the potential difference V2 across R3 . . What current I is needed to transmit 105 MW of power over a transmission line held at a voltage of 25.0 kV? Find the power loss P1055 that would occur in the transmission line if a 1.25 9 line is used to transmit 105 MW of power. What percent less does this represent? A certain single ion channel is selectively permeable to 1C\" and has a resistance of 1.15 GQ , therefore a current of potassium ions through the channel is possible. During an experiment, the channel is open for approximately 1.50 ms while the voltage across the channel is maintained at 3?.5 mV. How many K\" ions, N , travel through the channel during this time? The four resistors in the gure have an equivalent resistance of 169. The resistances are as follows: R. = 8.0 9, R2 = 4.0 9., and R3 = 8.052. Calculate the value of Rx. Find the drift velocity yd of conduction electrons in a gold wire of diameter 2.51 mm when a current of 0.163 A ows in it. The densit}r of conduction electrons in gold is 5.90 X 1029' m'3. Four resistors are connected to a battery as shown in the gure. The current through the battery is I , the battery's electromotive force (emf) is E = 1.20 V, and the resistor values are R. = R, R2 2 2R, R3 2 4R, and R4 2 3R. Find the voltages across each resistor. 5 II 5 || 4 R R m. 2R 4R Corrections : Question # 1 - + / RC At initial 10 = Ie 4 = 0 1.5 I. = 8090 1 . 854 X 10 4 A I think this is the correct answer T = RC = (8090 ) (965 x16) T = 0.03 5 1.854 * 10 4 ) 10.029 ) = 1.854 *W * 0.03 e In 0.0249 = In e - / 0.03 t = - In 0.0269 x 0.03 t = 0. 109 Question 2 - t 323 =12000 e In 0. 0269 = In e / 15x103 + = - In 0. 0249 x 15 x15 3 t = 0 054 s For Drift Velocity Vd = I 0.163 ng A 29 5. 90 X 10 /3 1.6 *10 17 ( 2.51 x10 3 ) Va = 3. 49 X10 m 14 S