On your first day at work as an electrical technician, you are asked to determine the resistance per meter of a long piece of wire. The company you work for is poorly equipped. You find a battery, a voltmeter, and an ammeter, but no meter for directly measuring resistance (an ohmmeter). You put the leads from the voltmeter across the terminals of the battery, and the meter reads 12.6 V. You cut off a 20.0-m length of wire and connect it to the battery, with an ammeter in series with it to measure the current in the wire. The ammeter reads 7.00 A. You then cut oil a 40.0-m length of wire and connect it to the battery, again with the ammeter in series to measure the current. The ammeter reads 4.20 A. Even though the equipment you have available to you is limited, your boss assures you of its high quality: The ammeter has very small resistance, and the voltmeter has very large resistance. What is the (resistance of 1 meter of wire?
Want to see the full answer?
Check out a sample textbook solutionChapter 25 Solutions
University Physics (14th Edition)
Additional Science Textbook Solutions
The Cosmic Perspective
Physics for Scientists and Engineers with Modern Physics
College Physics (10th Edition)
Modern Physics
Life in the Universe (4th Edition)
Tutorials in Introductory Physics
- The resistance between terminals a and b in Figure P27.36 is 75.0 . If the resistors labeled R have the same value, determine R. Figure P27.36arrow_forwardElectric current I enters a node with three resistors connected in parallel (Fig. CQ18.5). Which one of the following is correct? (a) I1 = I and I2 = I3 = 0. (b) I2 I1 and I2 I3. (c) V1 V2 V3 (d) I1 I2 I3 0. Figure CQ18.5arrow_forwardElectric current I enters a node with three resistors connected in parallel (Fig. CQ18.5). Which one of the following is correct? (a) I1 = I and I2 = I3 = 0. (b) I2 I1 and I2 I3. (c) V1 V2 V3 (d) I1 I2 I3 0. Figure CQ18.5arrow_forward
- In the circuit of Figure P27.20, the current I1 = 3.00 A and the values of for the ideal battery and R are unknown. What are the currents (a) I2 and (b) I3? (c) Can you find the values of and R? If so, find their values. If not, explain. Figure P27.20arrow_forwardYou want to determine the resistance value per meter for a very long wire. In the absence of an ohmmeter, you have at your disposal a battery, a voltmeter and an ammeter. First, you plug the voltmeter into the battery terminals and measure 10.7V. Then you cut a piece of the 20m wire and connect it to the battery, along with the ammeter in series. The reading on the ammeter is 6.00A. Then you cut a 40m piece of wire and connect it in the same way to the battery, with the ammeter in series. The reading is now 3.50A. You may think the voltmeter and ammeter are ideal, but the battery is not. What is the resistance value of 1 meter of wire?arrow_forwardA cylindrical aluminum pipe of length 1.41 m has an inner radius of 1.72 ×10-3 m and an outer radius of 3.10 ×10-3 m. The interior of the pipe is completely filled with copper. What is the resistance of this unit? (Hint: Imagine that the pipe is connected between the terminals of a battery and decide whether the aluminum and copper parts of the pipe are in series or in parallel.)arrow_forward
- The label on a battery-powered radio recommends the use of a rechargeable nickel-cadmium cell (nicads), although it has a 1.25-V open-circuit voltage, whereas an alkaline cell has a 1.58-V open-circuit voltage. The radio has a 3.2 Q2 resistance. Hint a. With a nicad cell, having an internal resistance of 0.04 02, what is the voltage supplied to the radio, if a single nicad cell is used? The voltage supplied to the radio is b. With an alkaline cell, having an internal resistance of 0.2 02, what is the voltage supplied to the radio, if a single alkaline cell is used? The voltage supplied to the radio is c. The radio's effective resistance is lowered when its volume is turned up. At what value of radio's resistance does a nicad cell begin to supply a greater voltage to the radio than an alkaline cell? Hint for (c) When the radio has an effective resistance of voltage can be obtained with a nicad cell. V. V. Q or smaller, a greaterarrow_forwardThree resistors, R1 = 17.3, R2 = 13.2, R3 = 78, are connected in series across a 16.6 V battery. What is the voltage drop (in Volts) across R1?arrow_forwardA student finds two ancient meters with numbered scales but no unit markings. He thinks that one is an ammeter and one is a voltmeter but doesn't know which is which. He measures the resistance of each, finding that meter A has a resistance of 5000 ohms and meter B has a resistance of 0.01 ohms. He can conclude that Group of answer choices A is the voltmeter and B is the ammeter. neither can be a useful meter. B is the voltmeter but A cannot be a useful meter. A is the voltmeter but B cannot be a useful meter. B is the voltmeter and A is the ammeter.arrow_forward
- A battery has an emf of ε = 19 V, an internal resistance r = 28 22, and is connected to a resistor of R = 75 22. Express the current I through the circuit in terms of ε, r and R. Calculate the numerical value of I in A. Express the terminal voltage 4V of the battery in terms of I and R. Calculate the numerical value of 4V in V.arrow_forwardTwo resistors, R1 = 21 Ω and R2 = 35 Ω are connected in parallel across a battery providing voltage ΔVbat = 5.7 V. What is the current through resistor R1?arrow_forwardNerve cells transmit electrical signals through their long tubular axons. These signals propagate due to a sudden rush of Na + ions, each with charge +e, into the axon. Measurements have revealed that typically about 5.8 x 1011 Na + ions enter each meter of the axon during a time of 15 milliseconds. What is the current during this inflow of charge in the axon?arrow_forward
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning