An oceanographer is studying how the ion concentration in seawater depends on depth. She makes a measurement by lowering into the water a pair of concentric metallic cylinders (Fig. P21.66) at the end of a cable and taking data to determine the resistance between these electrodes as a function of depth. The water between the two cylinders forms a cylindrical shell of inner radius ra, outer radius rb, and length L much larger than rb. The scientist applies a potential difference ΔV between the inner and outer surfaces, producing an outward radial current I. Let ρ represent the resistivity of the water. (a) Find the resistance of the water between the cylinders in terms of L, ρ, ra, an rb. (b) Express the resistivity of the water in terms of the measured quantities L, ra, rb, ΔV, and I.
Figure P21.66
Want to see the full answer?
Check out a sample textbook solutionChapter 21 Solutions
Principles of Physics: A Calculus-Based Text
- You are working at a company that manufactures electrical wire. Gold is the most ductile of all metals: it can be stretched into incredibly long, thin wires. The company has developed a new technique that will stretch 1.05 g of gold into a wire of length L-248 km and uniform diameter. Your supervisor gives you the task of determining the resistance of such a wire (in MQ) at 20.0°C. (The density of gold is 19.3 × 103 kg/m3.)arrow_forwardYou are working at a company that manufactures electrical wire. Gold is the most ductile of all metals: it can be stretched into incredibly long, thin wires. The company has developed a new technique that will stretch 1.00 g of gold into a wire of length L = 2.40 km and uniform diameter. Your supervisor gives you the task of determining the resistance of such a wire at 20.0°C.arrow_forwardYou are working at a company that manufactures electrical wire. Gold is the most ductile of all metals: it can be stretched into incredibly long, thin wires. The company has developed a new technique that will stretch 1.30 g of gold into a wire of length L = 2.52 km and uniform diameter. Your supervisor gives you the task of determining the resistance of such a wire (in MO) at 20.0°C. (The density of gold is 19.3 x 103 kg/m3.)arrow_forward
- A conducting spherical electrode of radius a is suspended with its center at a height h above the bottom of a large metal tank filled with a conducting medium having a conductivity s. Derive a formula for the resistance between the electrode and the metal tank. The tank is large enough to be considered as infinite. The electrode and the tank may be assumed to be made of perfect conductors.arrow_forwardElectrons flow through a 3.0-mm-diameter aluminum wire at 1.8×10−4 m/s. How many electrons move through a cross section of the wire each day?arrow_forwardThe battery capacity of a lithium ion battery in a digital music player is 750 mA-h. The manufacturer claims that the player can operate for eight hours if the battery is initially fully charged. Given this information, determine the number of electrons that flow through the player as you listen to your favorite songs for three hours.arrow_forward
- What is the resistance of a 21-cm-long column of blood in a 0.80-cm- diameter femoral artery? The conductivity of blood is 0.63 −¹ m¯¹.arrow_forwardMeasuring Blood Flow. Blood contains positive and negative ions and thus is a conductor. A blood vessel, therefore, can be viewed as an electrical wire. We can even picture the flowing blood as a series of parallel conducting slabs whose thickness is the diameter 5.00 mm of the vessel moving with speed. (See in the following figure.( Figure 1)) Figure X XBX X XX X X X X d 1 of 1 V If you expect that the blood will be flowing at 15.3 cm/s for a vessel 5.00 mm in diameter, what strength of magnetic field will you need to produce a potential difference of 1.00 mV ? Express your answer with the appropriate units. B = Submit Part C 0 R = μA Submit Value X Incorrect; Try Again; 5 attempts remaining T Previous Answers Request Answer = VE ΑΣΦ Determine the volume rate of flow (R). (Note: Although the method developed here is useful in measuring the rate of blood flow in a vessel, it is limited to use in surgery because measurement of the potential & must be made directly across the vessel.)…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_forward
- In a physics project, you need a wire to electrically heat a cryostat. You decide to create one with materials you have lying around. You find a 29.0-g piece of copper. The resistivity of copper is 1.68 x 10-8 Ω.m, and its density is 8.9 g/cm3. You will need to use all of your copper to create a solid cylindrical wire that has a total resistance of 0.75 Ω.Determine how long your wire will be, and what its diameter will be.arrow_forwardA teapot with a surface area of 790 cm2 is to be plated with silver. It is attached to the negative electrode of an electrolytic cell containing silver nitrate (Ag+ NO3−). The cell is powered by a 12.0-V battery and has a resistance of 1.90 Ω. If the density of silver is 1.05 104 kg/m3, over what time interval does a 0.133-mm layer of silver build up on the teapot?arrow_forwardA teapot with a surface area of 715 cm² is to be plated with silver. It is attached to the negative electrode of an electrolytic cell containing silver nitrate (Ag™ NO,). The cell is powered by a 12.0-V battery and has a resistance of 1.50 Q. If the density of silver is 1.05 × 10“ kg/m³, over what time interval does a 0.133-mm layer of silver build up on the teapot? You first need to calculate the total number of silver atoms contained in the plated volume of silver. Note that the nitrate ends up on the other electrode. h Need Help? Read Itarrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning