Physics, Books a la Carte Edition (5th Edition)
5th Edition
ISBN: 9780134020853
Author: James S. Walker
Publisher: PEARSON
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Chapter 21, Problem 13PCE
Transcranial Direct-Current Stimulation In a tDCS treatment procedure, 0.85 mA of current flows through a patient’s brain when there is a 7.4-V potential difference between the electrodes. What is the equivalent resistance between the electrodes?
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Chapter 21 Solutions
Physics, Books a la Carte Edition (5th Edition)
Ch. 21.1 - Enhance Your Understanding 1. The following...Ch. 21.2 - Enhance Your Understanding 2. If the voltage and...Ch. 21.3 - Enhance Your Understanding 3. In the following...Ch. 21.4 - The two circuits shown in Figure 21-17 have...Ch. 21.5 - Prob. 5EYUCh. 21.6 - Do two capacitors give a larger equivalent...Ch. 21.7 - Give a symbolic expression for the current that...Ch. 21 - Your body is composed of electric charges. Does it...Ch. 21 - Suppose you charge a comb by rubbing it through...Ch. 21 - An electron moving through a wire has an average...
Ch. 21 - Are car headlights connected in series or...Ch. 21 - Is it possible to connect a group of resistors of...Ch. 21 - What physical quantity do resistors connected in...Ch. 21 - What physical quantity do resistors connected in...Ch. 21 - Explain how electrical devices can begin operating...Ch. 21 - Explain the difference between resistivity and...Ch. 21 - Explain why birds can roost on high-voltage wires...Ch. 21 - Consider the circuit shown in Figure 21-36, in...Ch. 21 - A flashlight bulb carries a current of 0.38 A for...Ch. 21 - Predict/Calculate A car battery does 360 J of work...Ch. 21 - Highly sensitive ammeters can measure currents as...Ch. 21 - A television set connected to a 120-V outlet...Ch. 21 - BIO Pacemaker Batteries Pacemakers designed for...Ch. 21 - A conducting wire is quadrupled in length and...Ch. 21 - Figure 21-37 shows a plot of current versus...Ch. 21 - Predict/Explain Current-versus-voltage plots for...Ch. 21 - Prob. 9PCECh. 21 - When a potential difference of 12 V is applied to...Ch. 21 - Prob. 11PCECh. 21 - Prob. 12PCECh. 21 - Transcranial Direct-Current Stimulation In a tDCS...Ch. 21 - The four conducting cylinders shown in Figure...Ch. 21 - Predict/Calculate A bird lands on a bare copper...Ch. 21 - Prob. 16PCECh. 21 - Predict/Calculate BIO Current Through a Cell...Ch. 21 - Prob. 18PCECh. 21 - Prob. 19PCECh. 21 - BIO Resistance and Current in the Human Finger The...Ch. 21 - If a potential difference V is maintained between...Ch. 21 - Light A has four times the power rating of light B...Ch. 21 - Two lightbulbs operate on the same potential...Ch. 21 - Problems and Conceptual Exercises Section 21-3...Ch. 21 - A 65-V generator supplies 4.8 kW of power. How...Ch. 21 - A portable CD player operates with a current of 18...Ch. 21 - Find the power dissipated in a 22- electric heater...Ch. 21 - The current in a 120-V reading lamp is 2.6 A. If...Ch. 21 - Circuit A in a house has a voltage of 208 V and is...Ch. 21 - Predict/Calculate A 65-W lightbulb operates on a...Ch. 21 - Rating Car Batteries Car batteries are rated by...Ch. 21 - Predict/Explain A dozen identical lightbulbs are...Ch. 21 - A circuit consists of three resistors, R1 R2 R3,...Ch. 21 - Predict/Explain Two resistors are connected in...Ch. 21 - What is the minimum number of 88- resistors that...Ch. 21 - Find the equivalent resistance between points A...Ch. 21 - A 9.00-V battery is connected across the terminals...Ch. 21 - Holiday Lights In a string of holiday lights, 50...Ch. 21 - Your toaster has a power cord with a resistance of...Ch. 21 - Prob. 40PCECh. 21 - Predict/Calculate Three resistors, 11, 53 , and R,...Ch. 21 - A circuit consists of a battery connected to three...Ch. 21 - Predict/Calculate Three resistors, 22 , 67 , and...Ch. 21 - Prob. 44PCECh. 21 - The equivalent resistance between points A and B...Ch. 21 - Find the equivalent resistance between points A...Ch. 21 - How many 23-W lightbulbs can be connected in...Ch. 21 - The circuit in Figure 21-43 includes a battery...Ch. 21 - Predict/Calculate A 12-V battery is connected to...Ch. 21 - Predict/Calculate The terminals A and B in Figure...Ch. 21 - Predict/Calculate Suppose the battery in Figure...Ch. 21 - Predict/Calculate The current flowing through the...Ch. 21 - Predict/Calculate Four identical resistors are...Ch. 21 - Find the magnitude and direction (clockwise or...Ch. 21 - Predict/Calculate Suppose the polarity of the...Ch. 21 - Predict/Calculate It is given that point A in...Ch. 21 - Consider the circuit shown in Figure 21-47. Find...Ch. 21 - Suppose point A is grounded (V = 0) in Figure...Ch. 21 - Predict/Calculate (a) Find the current in each...Ch. 21 - Two batteries and three resistors are connected as...Ch. 21 - Two capacitors, C1 = C and C2 = 2C, are connected...Ch. 21 - Predict/Explain Two capacitors are connected in...Ch. 21 - Predict/Explain Two capacitors are connected in...Ch. 21 - A 252-F capacitor is connected in series with a...Ch. 21 - A 36-F capacitor is connected in parallel with an...Ch. 21 - Find the equivalent capacitance between points A...Ch. 21 - A 15-V battery is connected to three capacitors in...Ch. 21 - Three different circuits, each containing a switch...Ch. 21 - Terminals A and B in Figure 21-50 are connected to...Ch. 21 - Predict/Calculate You would like to add a second...Ch. 21 - Two capacitors, one 7.5 F and the other 15 F, are...Ch. 21 - The equivalent capacitance of the capacitors shown...Ch. 21 - With the switch in position A, the 11.2-F...Ch. 21 - The switch on an RC circuit is closed at t = 0....Ch. 21 - The capacitor in an RC circuit (R = 120 , C = 45...Ch. 21 - Three RC circuits have the emf, resistance, and...Ch. 21 - Consider an RC circuit with = 12.0 V, R = 195 ,...Ch. 21 - The resistor in an RC circuit has a resistance of...Ch. 21 - A flash unit for a camera has a capacitance of...Ch. 21 - Figure 21-54 shows a simplified circuit for a...Ch. 21 - Nerve Impulse Propagation The speed with which...Ch. 21 - Predict/Calculate Consider the RC circuit shown in...Ch. 21 - CE Consider the circuit shown in Figure 21-56, in...Ch. 21 - CE Predict/Explain (a) Referring to Problem 83 and...Ch. 21 - CE Consider the circuit shown in Figure 21-57, in...Ch. 21 - CE Predict/Explain (a) When the switch is closed...Ch. 21 - Suppose that points A and B in Figure 21-41 are...Ch. 21 - CE The circuit shown in Figure 21-58 shows a...Ch. 21 - CE The three circuits shown in Figure 21-59 have...Ch. 21 - Electrical Safety Codes For safety reasons,...Ch. 21 - A portable CD player uses a current of 7.5 mA at a...Ch. 21 - An electrical heating coil is immersed in 6.6 kg...Ch. 21 - Predict/Calculate Consider the circuit shown in...Ch. 21 - Prob. 94GPCh. 21 - BIO Pacemaker Pulses A pacemaker sends a pulse to...Ch. 21 - Three resistors (R,12R,2R) are connected to a...Ch. 21 - Predict/Calculate Suppose we connect a 12.0-V...Ch. 21 - National Electric Code In the United States, the...Ch. 21 - Solar Panel Power The current-versus-voltage plot...Ch. 21 - Predict/Calculate A 15.0-V battery is connected to...Ch. 21 - When two resistors, R1 and R2, are connected in...Ch. 21 - The circuit shown in Figure 21-62 is known as a...Ch. 21 - BIO Footwear Safety The American National...Ch. 21 - BIO Footwear Safety The American National...Ch. 21 - BIO Footwear Safety The American National...Ch. 21 - The standard specifies that footwear should be...Ch. 21 - Referring to Example 21-13 Suppose the three...Ch. 21 - Referring to Example 21-13 Suppose R1 = R2 = 225 ...Ch. 21 - Predict/Calculate Referring to Example 21-18...Ch. 21 - Predict/Calculate Referring to Example 21-18...
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