College Physics
OER 2016 Edition
ISBN: 9781947172173
Author: OpenStax
Publisher: OpenStax College
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 20, Problem 14CQ
The power dissipated in a resistor is given by P = V2/R, which means power decreases if resistance increases. Yet this power is also given by P = I2R, which means power increases if resistance increases. Explain why there is no contradiction here.
Expert Solution & Answer
Trending nowThis is a popular solution!
Chapter 20 Solutions
College Physics
Ch. 20 - Can a wire carry a current and still be...Ch. 20 - Car batteries are rated in ampere-hours (A h )....Ch. 20 - If two different wires having identical...Ch. 20 - Why are two conducting paths from a voltage source...Ch. 20 - In cars, one battery terminal is connected to the...Ch. 20 - Why isn't a bird sitting on a high-voltage power...Ch. 20 - The IR drop across a resistor means that there is...Ch. 20 - How is the I R drop in a resistor similar to the...Ch. 20 - In which of the three semiconducting materials...Ch. 20 - Prob. 10CQ
Ch. 20 - If aluminum and copper wires of the same length...Ch. 20 - Explain why R=R0(1 + a?T) for the temperature...Ch. 20 - Why do incandescent lightbulbs grow dim late in...Ch. 20 - The power dissipated in a resistor is given by P =...Ch. 20 - Give an example of a use of AC power other than in...Ch. 20 - Why do voltage, current, and power go through zero...Ch. 20 - You are riding in a train, gazing into the...Ch. 20 - Using an ohmmeter, a student measures the...Ch. 20 - What are the two major hazards of electricity?Ch. 20 - Why isn’t a short circuit a shock hazard?Ch. 20 - What determines the severity of a shock? Can you...Ch. 20 - An electrified needle is used to burn off warts,...Ch. 20 - Some surgery is performed with high-voltage...Ch. 20 - Some devices often used in bathrooms, such as...Ch. 20 - We are often advised to not flick electric...Ch. 20 - Before working on a power transmission line,...Ch. 20 - Why is the resistance of wet skin so much smaller...Ch. 20 - Could a person on intravenous infusion (an IV) be...Ch. 20 - In view of the small currents that cause shock...Ch. 20 - Prob. 30CQCh. 20 - Define depolarization, repolarization, and the...Ch. 20 - Explain the properties of myelinated nerves in...Ch. 20 - What is the current in milliamperes produced by...Ch. 20 - A total of 600 C of charge passes through a...Ch. 20 - What is the current when a typical static charge...Ch. 20 - Find the current when 2.00 nC jumps between your...Ch. 20 - A large lightning bolt had a 20,000-A current and...Ch. 20 - The 200-A current through a spark plug moves 0.300...Ch. 20 - Prob. 7PECh. 20 - During open-heart surgery, a defibrillator can be...Ch. 20 - (a) A defibrillator passes 12.0 A of current...Ch. 20 - A clock battery wears out after moving 10,000 C of...Ch. 20 - The batteries of a submerged non-nuclear submarine...Ch. 20 - Electron guns are used in X-ray tubes. The...Ch. 20 - A large cyclotron directs a beam of He ++ nuclei...Ch. 20 - Repeat the above example on Example 20.3, but for...Ch. 20 - Using the results of the above example on Example...Ch. 20 - A 14-gauge copper wire has a diameter of 1.628 mm....Ch. 20 - Prob. 17PECh. 20 - What current flows through the bulb of a 3.00-V...Ch. 20 - Calculate the effective resistance of a pocket...Ch. 20 - What is the effective resistance of a car’s...Ch. 20 - How many volts are supplied to operate an...Ch. 20 - (a) F ind the voltage drop in an extension cord...Ch. 20 - A power transmission line is hung from metal...Ch. 20 - What is the resistance of a 20.0-m-long piece of...Ch. 20 - The diameter of 0-gauge copper wire is 8.252 mm....Ch. 20 - If the 0.100-mm diameter tungsten filament in a...Ch. 20 - Find the ratio of the diameter of aluminum to...Ch. 20 - What current flows through a 2.54-cm-diameter rod...Ch. 20 - (a) To what temperature must you raise a copper...Ch. 20 - A resistor made of Nichrome wire is used in an...Ch. 20 - Of what material is a resistor made if its...Ch. 20 - An electronic device designed to operate at any...Ch. 20 - a) Of what material is a wire made, if it is 25.0...Ch. 20 - Assuming a constant temperature coefficient of...Ch. 20 - A wire is drawn through a die, stretching it to...Ch. 20 - A copper wire has a resistance of 0.500at 20.0°C,...Ch. 20 - (a) Digital medical thermometers determine...Ch. 20 - Integrated Concepts (a) Redo Exercise 20.25 taking...Ch. 20 - Unreasonable Results (a) To what temperature must...Ch. 20 - What is the power of a 1.00 102 MV lightning boit...Ch. 20 - What power is supplied to the starter motor of a...Ch. 20 - Prob. 42PECh. 20 - How many watts does a flashlight that has 6.00102C...Ch. 20 - Find the power dissipated in each of these...Ch. 20 - Verify that the units of a volt-ampere are watts,...Ch. 20 - Show that the units 1 V2/=1W , as implied by the...Ch. 20 - Show that the units 1 A 2 = 1W, as implied by the...Ch. 20 - Verify the energy unit equivalence that 1 kWh =...Ch. 20 - Electrons in an X-ray tube are accelerated through...Ch. 20 - Prob. 50PECh. 20 - With a 1200-W toaster, how much electrical energy...Ch. 20 - What would be the maximum cost of a CFL such that...Ch. 20 - Some makes of older cars have 6.00-V electrical...Ch. 20 - Alkaline batteries have the advantage of putting...Ch. 20 - A cauterizer, used to stop bleeding in surgery,...Ch. 20 - The average television is said to be on 6 hours...Ch. 20 - An old lightbulb draws only 50.0 W, rather than...Ch. 20 - -gauge copper wire has a diameter of 9.266 mm....Ch. 20 - Prob. 59PECh. 20 - Integrated Concepts (a) What energy is dissipated...Ch. 20 - Integrated Concepts What current must be produced...Ch. 20 - Integrated Concepts How much time is needed for a...Ch. 20 - Prob. 63PECh. 20 - Prob. 64PECh. 20 - Integrated Concepts A light-rail commuter train...Ch. 20 - Integrated Concepts (a) An aluminum power...Ch. 20 - Integrated Concepts (a) An immersion heater...Ch. 20 - Integrated Concepts (a) What is the cost of...Ch. 20 - Unreasonable Results (a) What current is needed to...Ch. 20 - Unreasonable Results (a) What current is needed to...Ch. 20 - Construct Your Own Problem Consider an electric...Ch. 20 - (a) What is the hot resistance of a 25-W light...Ch. 20 - Certain heavy industrial equipment uses AC power...Ch. 20 - A certain circuit breaker trips when the rms...Ch. 20 - Military aircraft use 400-Hz AC power, because it...Ch. 20 - A North American tourist takes his 25.0-W, 120-V...Ch. 20 - In this problem, you will verify statements made...Ch. 20 - A small office-building air conditioner operates...Ch. 20 - What is the peak power consumption of a 12G-V AC...Ch. 20 - What is the peak current through a 500-W room...Ch. 20 - Two different electrical devices have the same...Ch. 20 - Nichrome wire is used in some radiative heaters....Ch. 20 - Find the time after t = 0 when the instantaneous...Ch. 20 - (a) At what two times in the first period...Ch. 20 - (a) Haw much power is dissipated in a short...Ch. 20 - What voltage is involved in a 1.44-kW short...Ch. 20 - Find the current through a person and identify the...Ch. 20 - While taking a bath, a person touches the metal...Ch. 20 - Foolishly trying to fish a burning piece of bread...Ch. 20 - (a) During surgery, a current as small as 20.0 ?...Ch. 20 - (a) What is the resistance of a 220-V AC short...Ch. 20 - A heart defibrillator passes 10.0 A through a...Ch. 20 - Integrated Concepts A short circuit in a 120-V...Ch. 20 - Construct Your Own Problem Consider a person...Ch. 20 - Prob. 95PECh. 20 - Prob. 96PECh. 20 - Prob. 1TPCh. 20 - Prob. 2TPCh. 20 - Prob. 3TPCh. 20 - Prob. 4TPCh. 20 - Prob. 5TPCh. 20 - Prob. 6TPCh. 20 - Prob. 7TPCh. 20 - Prob. 8TPCh. 20 - Prob. 9TPCh. 20 - Prob. 10TPCh. 20 - Prob. 11TPCh. 20 - Prob. 12TPCh. 20 - Prob. 13TPCh. 20 - Prob. 14TPCh. 20 - Prob. 15TP
Additional Science Textbook Solutions
Find more solutions based on key concepts
5. A 65 kg gymnast wedges himself between two closely spaced vertical walls by pressing his hands and feet ag...
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
Police Captain Jeffers has suffered a myocardial infarction. a. Explain to his (nonmedically oriented) family w...
Human Physiology: An Integrated Approach (8th Edition)
Use a globe or map to determine, as accurately as possible, the latitude and longitude of Athens, Greece.
Applications and Investigations in Earth Science (9th Edition)
If someone at the other end of a room smokes a cigarette, you may breathe in some smoke. The movement of smoke ...
Campbell Essential Biology with Physiology (5th Edition)
Define histology.
Fundamentals of Anatomy & Physiology (11th Edition)
2. Define equilibrium population. Outline the conditions that must be met for a population to stay in genetic e...
Biology: Life on Earth (11th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Power P0 = I0 V0 is delivered to a resistor of resistance R0. If the resistance is doubled (Rnew = 2R0) while the voltage is adjusted such that the current is constant, what are the ratios (a) Pnew/P0 and (b) Vnew/V0? If, instead, the resistance is held constant while Pnew = 2P0, what are the ratios (c) Vnew/V0, and (d) Inew/I0?arrow_forwardExplain why R=R0(1 + a?T) for the temperature variation of the resistance R of an object is not as accurate as P=P0(1 + a?T) which gives the temperature variation of resistivity P.arrow_forwardReview. When a straight wire is warmed, its resistance is given by R = R0,[1 + a(T T0)] according to Equation 27.20, where a is the temperature coefficient of resistivity. This expression needs to be modified if we include the change in dimensions of the wire due to thermal expansion. For a copper wire of radius 0.100 0 mm and length 2.000 m, find its resistance at 100.0C, including the effects of both thermal expansion and temperature variation of resistivity. Assume the coefficients are known to four significant figures.arrow_forward
- For the circuit shown in Figure P28.55. the ideal voltmeter reads 6.00 V and the ideal ammeter reads 3.00-k. Find (a) the value of K, (b) the emf of the battery, and (c) the voltage across the 3.00-kft resistor.arrow_forwardConsider a series RC circuit as in Figure P28.38 for which R = 1.00 M, C = 5.00 F, and = 30.0 V. Find (a) the time constant of the circuit and (b) the maximum charge on the capacitor after the switch is thrown closed. (c) Find the current in the resistor 10.0 s after the switch is closed.arrow_forwardA capacitor with initial charge Q0 is connected across a resistor R at time t = 0. The separation between the plates of the capacitor changes as d = d0/(1 + t) for 0 t 1 s. Find an expression for the voltage drop across the capacitor as a function of time.arrow_forward
- The values of the components in a simple series RC circuit containing a switch (Fig. P21.53) are C = 1.00 F, R = 2.00 106 , and = 10.0 V. At the instant 10.0 s after the switch is closed, calculate (a) the charge on the capacitor, (b) the current in the resistor, (c) the rate at which energy is being stored in the capacitor, and (d) the rate at which energy is being delivered by the battery.arrow_forwardFigure P29.60 shows a simple RC circuit with a 2.50-F capacitor, a 3.50-M resistor, a 9.00-V emf, and a switch. What are a. the charge on the capacitor, b. the current in the resistor, c. the rate at which the capacitor is storing energy, and d. the rate at which the battery is delivering energy exactly 7.50 s alter the switch is closed?arrow_forwardWhen the switch is open in Figure 18.8, power Po is delivered to the resistor R1. When the switch is closed, which of the following is true about the power Pc delivered to R1? (Neglect the internal resistance of the battery.) (a) Pc Po (b) Pc = Po (c) Pc Po Figure 18.8 (Quick Quizzes 18.5 and 18.6)arrow_forward
- Figure P18.26 shows a voltage divider, a circuit used to obtain a desired voltage Vout from a source voltage . Determine the required value of R2 if = 5.00 V, Vout = 1.50 V and R1 = 1.00 103 (Hint: Use Kirchhoff's loop rule, substituting Vout = IR2, to find the current. Then solve Ohms law for R2. Figure P18.26arrow_forwardResistors are commonly rated at 18W,14W,12W ,1 W and 2 W for use in electrical circuits. If a current of1 = 2.00 A is accidentally passed through a R=1.00 resistor rated at 1 W, what would be the most probable outcome? Is there anything that can be done to prevent such an accident?arrow_forwardThe circuit shown in Figure P28.78 is set up in the laboratory to measure an unknown capacitance C in series with a resistance R = 10.0 M powered by a battery whose emf is 6.19 V. The data given in the table are the measured voltages across the capacitor as a function of lime, where t = 0 represents the instant at which the switch is thrown to position b. (a) Construct a graph of In (/v) versus I and perform a linear least-squares fit to the data, (b) From the slope of your graph, obtain a value for the time constant of the circuit and a value for the capacitance. v(V) t(s) In (/v) 6.19 0 5.56 4.87 4.93 11.1 4.34 19.4 3.72 30.8 3.09 46.6 2.47 67.3 1.83 102.2arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
College PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College
College Physics
Physics
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
College Physics
Physics
ISBN:9781285737027
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
Ohm's law Explained; Author: ALL ABOUT ELECTRONICS;https://www.youtube.com/watch?v=PV8CMZZKrB4;License: Standard YouTube License, CC-BY