A negative test charge of 50 µC is 5 meters from point A and 10 m from point B. Find the potential difference between points A and B. * -45000 V -90000 V 90000 V 45000 V It is defined to be the ratio of the potential difference (or voltage) across a conductor to the current through the material. * Resistance Electric Current Ampere Voltage It is the time rate of flow of charge. * Resistance Ampere Electric Current Voltage

A negative test charge of 50 µC is 5 meters from point A and 10 m from point B. Find the potential difference between points A and B. * -45000 V -90000 V 90000 V 45000 V It is defined to be the ratio of the potential difference (or voltage) across a conductor to the current through the material. * Resistance Electric Current Ampere Voltage It is the time rate of flow of charge. * Resistance Ampere Electric Current Voltage

Physics for Scientists and Engineers

10th Edition

ISBN:9781337553278

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter27: Direct-current Circuits

Section: Chapter Questions

Problem 14P: For the purpose of measuring the electric resistance of shoes through the body of the wearer...

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(a) A defibrillator sends a 6.00-A current through the chest of a patient by applying a 10,000-V potential as in the figure below. What is the resistance of the path? (b) The defibrillator paddles make contact with the patient through a conducting gel that greatly reduces the path resistance. Discuss the difficulties that would ensue if a larger voltage were used to produce the same current through the patient, but with the path having perhaps 50 times the resistance. (Hint: The current must be about the same, so a higher voltage would imply greater power. Use this equation for power: P=I2 RP = .)
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A 1,00-?O voltmeter is placed in parallel with a 75.0kresistor in a circuit, (a) Draw a circuit diagram of the connection, (b) What is the resistance of the combination? If the voltage across the combination is kept the same as it was across the 75.0-kresistor alone, what is the percent increase in current? (d) If the current through the combination is kept the same as it was through the 75.0-kresistor alone, what is the percentage decrease in voltage? (e) Are the changes found in parts (c) and (d) significant? Discuss.
For the purpose of measuring the electric resistance of shoes through the body of the wearer standing on a metal ground plate, the American National Standards Institute (ANSI) specifies the circuit shown in Figure P27.14. The potential difference V across the 1.00-M resistor is measured with an ideal voltmeter. (a) Show that the resistance of the footwear is Rshoes=50.0VVV (b) In a medical test, a current through the human body should not exceed 150 A. Can the current delivered by the ANSI-specified circuit exceed 150 A? To decide, consider a person standing barefoot on the ground plate. Figure P27.14
Figure P27.48 shows a circuit model for the transmission of an electrical signal such as cable TV to a large number of subscribers. Each subscriber connects a load resistance RL between the transmission line and the ground. The ground is assumed to be at zero potential and able to carry any current between any ground connections with negligible resistance. The resistance of the transmission line between the connection points of different subscribers is modeled as the constant resistance RT. Show that the equivalent resistance across the signal source is Req=12[(4RTRL+RT2)1/2+RT] Suggestion: Because the number of subscribers is large, the equivalent resistance would not change noticeably if the first subscriber canceled the service. Consequently, the equivalent resistance of the section of the circuit to the right of the first load resistor is nearly equal to Req. Figure P27.48
The rather simple circuit shown below is known as a voltage divider. The symbol consisting of three horizontal lines is represents “ground” and can be defined as the point where the potential is zero. The voltage divider is widely used in circuits and a single voltage source can be used to provide reduced voltage to a load resistor as shown in the second part of the figure, (a) What is the output voltage Vout of circuit (a) in terms of R1,R2,andVin (b) What is the output voltage Vout of circuit (b) in terms of R1,R2,RLandVin
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