Concept explainers
Wires aren’t really ideal. The voltage drop across a current-carrying wire can be significant unless the resistance of the wire is quite low. Suppose a 50 ft extension cord is being used to provide power to an electric lawn mower. The cord carries a 10 A current. The copper wire in a typical extension cord has a 1.3 mm diameter. What is the voltage drop across a 50 ft length of wire at this current?
Want to see the full answer?
Check out a sample textbook solutionChapter 22 Solutions
College Physics: A Strategic Approach (3rd Edition)
Additional Science Textbook Solutions
Lecture- Tutorials for Introductory Astronomy
University Physics with Modern Physics (14th Edition)
University Physics Volume 1
Essential University Physics: Volume 1 (3rd Edition)
Glencoe Physical Science 2012 Student Edition (Glencoe Science) (McGraw-Hill Education)
College Physics: A Strategic Approach (4th Edition)
- B. A silver wire 2.6 mm in diameter transfers a charge of 420 C in 80 min. Silver contains 5.8 x 1028 free electrons per cubic meter. (a) What is the current in the wire? (b) What is the magnitude of the drift velocity of the electrons in the wire?arrow_forwardThe electron beam inside an old television picture tube is 0.40 mmmm in diameter and carries a current of 50 μA. This electron beam impinges on the inside of the picture tube screen. What is the current density in the electron beam and how many electrons strike the screen each second? The electrons move with a velocity of 3.0×107m/s. What electric field strength is needed to accelerate electrons from rest to this velocity in a distance of 5.0 mm? Each electron transfers its kinetic energy to the picture tube screen upon impact. What is the power delivered to the screen by the electron beam?arrow_forwardA lightning rod on top of a building consists of an iron spike 1.5 m long with a circular crosssection of diameter 1.5 cm. During a lightning strike, the rod carries a current of 1000 A. What is the potential difference across the rod when this current flows? The resistivity of iron is 1.0 x 10-7 Ωm.arrow_forward
- Copper has 8.5×1028 electrons per cubic meter. How many electrons are there in a 50.0 cm length of 12-gauge copper wire (diameter 2.05 mm)? If a current of 2.10 A is flowing in the wire, what is the average drift speed of the electrons along the wire? (There are 6.24×1018 electrons in 1 coulomb of charge.)arrow_forwardA 7-Ampere current runs through a 12-gauge copper wire (diameter = 2.05 mm) and through a light bulb. Copper has 8.5 x 1028 free electrons per cubic meter. (a) How many electrons pass through the light bulb each second? (b) What is the current density in the wire? (c) At what speed does a typical electron pass by any given point in the wire?arrow_forwardVariations in the resistivity of blood can give valuable clues to changes in the blood’s viscosity and other properties. The resistivity is measured by applying a small potential difference and measuring the current. Suppose a medical device attaches electrodes into a 1.5-mm-diameter vein at two points 5.0 cm apart. What is the blood resistivity if a 9.0 V potential difference causes a 230 μA current through the blood in the vein?arrow_forward
- Variations in the resistivity of blood can give valuable clues to changes in the blood's viscosity and other properties. The resistivity is measured by applying a small potential difference and measuring the current. Suppose a medical device attaches electrodes into a 1.5-mm-diameter vein at two points 5.0 cm apart. What is the blood resistivity if a 9.0 V potential difference causes a 240 μA current through the blood in the vein?Express your answer in ohm meters.arrow_forwardA long wire with a radius of 0.450 cm carries a current. The potential difference across a 3.10 m long section of this wire is 14.0 V, and the wire carries a current of 0.350 A. (a) What is the resistance (in 0) of the 3.10 m long section of wire? Ω (b) What is the resistivity (in N : m) of the wire? Ω. marrow_forwardA copper wire and an iron wire of equal length L and diameter d are joined and a potential difference V is applied between the ends of the composited wire. calculate a) the potential difference across each wire. b) The current density in each wire, c) the electric field in each wire. L=10 m, d=2.0 mm, V=100voltarrow_forward
- Please answer this excercise. This is not a graded question. 1. A silver wire 1.00 mm in diameter transfers a charge of 65.0 C in 1 hr. 15.0 min. Silver contains 5.0 × 1028 eoectrons per cubic meter. What is the current in the wire? What is the magnitude of the drift velocity of the electrons in the wire? 2. An aluminum wire carrying a current has a diameter of 0.600 mm. The electric field in the wire is 0.640 V/m. What is tue current carried by the wire? What is the potential difference between two points if the wires are 12.0m apart? What is the resistance of a 12.0m length of wire?arrow_forwardIf you touch the two terminals of a power supply with your two fingertips on opposite hands, the potential difference will produce a current through your torso. The maximum safe current is approximately 5 mA.a. If your hands are completely dry, the resistance of your body from fingertip to fingertip is approximately 500 kΩ. If you accidentally touch both terminals of your 120 V household electricity supply with dry fingers, will you receive a dangerous shock?b. If your hands are moist, your resistance drops to approximately 1 kΩ. If you accidentally touch both terminals of your 120 V household supply with moist fingers, will you receive a dangerous shock?arrow_forwardThe conduction electrons in a cylindrical, current-carrying wire have a drift velocity of 0.35 mm/s. The wire has a radius of 1.0 mm and contains 8.6 x 1028 conduction electrons per m3. What is the current in the wire? (The magnitude of the charge of an electron is 1.602 x 10-19 C.) a. 3.0 A b. 6.0 A c. 9.0 A d. 12 A e. 15 Aarrow_forward
- Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning