Concept explainers
BIO SPIDERWEB
*Based on F. Vollrath and D. Edmonds. “Consequences of electrical conductivity in an orb spider’s capture web.” Natunvissenschaften (100:12. December 2013, pp. 1163-69).
25.79 What is the best explanation for the behavior exhibited in the data? (a) Longer threads can carry more current than shorter threads do and so make better electrical conductors, (b) The thread stops being a conductor when it is stretched to 13 mm, due to breaks that occur in the thin coating, (c) As the thread is stretched, the coating thins and its resistance increases; as the thread is relaxed, the coating returns nearly to its original state, (d) The resistance of the thread increases with distance from the end of the thread.
Want to see the full answer?
Check out a sample textbook solutionChapter 25 Solutions
University Physics (14th Edition)
Additional Science Textbook Solutions
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
University Physics with Modern Physics (14th Edition)
Applied Physics (11th Edition)
College Physics: A Strategic Approach (4th Edition)
Conceptual Physical Science (6th Edition)
Conceptual Physics (12th Edition)
- Cylindrical-conductors has inner and outer radii of 2 mm and 50 mm, respectively. If V(p = 2 mm) = 150 V and V(p = 50 mm) = 0 V, &r 10, dielectric conductivity 5x10-4 s/m, the dielectric resistance equals to 803.96 2 1024.59 2 1153.66 Q 1245.23 2arrow_forward- C. Problems C1. For the configuration of conductors depicted below, find the electrodynamic force F2 = ? developed in conductor 2, given: 3 I =1000 A L=2m I, I I2 = 2500 A а%3D2 ст I3 = 3000 A b= 6 cm L I4 = 5000 A c = 4 cm barrow_forwardA wire with a radius of 7.72mm is made of a conducting material that has an atomic mass of 49.4 grams/mole and a mass density of 7.78x10³ kg/m³. You can assume that each atom of the material has one free electron associated with it. What is the drift velocity in a 17.6 cm long section of wire that is carrying 704 Amps? Assume 3 significant digits and units of mm/s. Watch out for units!arrow_forward
- How many free electrons are there in a rectangular block of a conductor whose dimension is 8 m by 4 m by 3 m? The electrons of this conductor have a drift velocity of 4 m/s when a 9.6 A of current is applied thru a cross-sectional area of 0.005 m^2. Use electronic charge of 1.6 x 10 –19 coulomb pere lectron. Express your answer in scientific notation whose unit is electrons per cubic meter.arrow_forwardA current of 0.300 A through your chest can send your heart into fibrillation, ruining the normal rhythm of heartbeat and disrupting the flow of blood (and thus oxygen) to your brain. If that current persists for 2.00 min, how many conduction electrons pass through your chest?arrow_forwardz Q. The ends of the cylinder are made of conducting discs and the space between these discs are filled with an inhomogeneous ohmic medium whose conductivity o = L/z'. Where L is the separation distance of the L discs. A d-c voltage Vo is applied across the discs as shown on the right. Determine V. a) The total resistance between the discs b) The surface charge densities on the discs c) The volume charge density and the total amount of charge between the discs y Narrow_forward
- It turns out that humans are only harmed by current, not voltage, to the point where even 0.2 amps is almost certainly lethal. Yet for some reason we always see signs for “Danger: High Voltage”, even though voltage literally cannot hurt you. Why should you still stay away from high voltage objects, and does that mean you should worry about all objects that can supply voltage? It might be helpful to know that a dry human body has about 100,000 ohms of resistance, and we can’t feel current below 0.001 Amps.arrow_forwardA conducting cylinder has length 36 mm and radius 17 mm. The conductor is then reshaped into a smaller cylinder, a quarter of the original length, and half that of the original diameter. The conductivity of the material is 6x107/Ω.m. Enter your answer in scientific notation with 2 significant figures. Please calculate the resistance for the reshaped conductorarrow_forwardA current of 0.300 A through your chest can send your heart into fibrillation, ruining the normal rhythm of heart beat and disrupting the flow of blood (and thus oxygen) to your brain. If that current persists for 1.39 min, how many conduction electrons pass through your heart?arrow_forward
- Asaparrow_forwardWhat is a characteristic that is common to a steel sheet, copper wire. metal paper clip and a wooden spoon does not have? * O all are conductors and allow electrons to flow except for the wooden spoon O all are insulators and allow protons to flow except the wooden spoon O all are insulators and allow electrons to flow except for the wooden spoon O all are conductors and allow protons to flow except for the wooden spoon.arrow_forwardIn the classic model for electrical conduction, electron mobility u in a metal wire is defined as where v, is the drift velocity of the electrons and E is the electric field in the metal. This parameter is a measure of how freely electrons can travel through a metal when an electric field is applied, such as when the ends of a metal wire are connected to a potential difference. (a) Show that where a is the conductivity of the metal, n is the number density of the charge carriers, and q is the charge on each carrier. (Submit a file with a maximum size of 1 MB.) Choose File no file selected This answer has not been graded yet. (b) B = AVH is often written as AVH - R IB where R, is the Hall coefficient of the metal. Show that the following is true. (Submit a file with a maximum size of 1 MB.) Hyo -n (Choose File no file selected This answer has not been graded yet (c) The table below shows some measured values of Hall coefficients for some elemental materials. What is an average number…arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning