Concept explainers
BIO Nerve Cells Nerve cells are long, thin cylinders along which electrical disturbances (nerve impulses) travel. The cell membrane of a typical nerve cell consists of an inner and an outer wall separated by a distance of 0.10 μm The electric field within the cell membrane is 7.0 × 105 N/C. Approximating the cell membrane as a parallel-plate capacitor, determine the magnitude of the charge density on the inner and outer cell walls.
Want to see the full answer?
Check out a sample textbook solutionChapter 19 Solutions
Physics, Books a la Carte Edition (5th Edition)
Additional Science Textbook Solutions
Human Anatomy & Physiology (2nd Edition)
Concepts of Genetics (12th Edition)
Genetic Analysis: An Integrated Approach (3rd Edition)
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
Campbell Biology (11th Edition)
Microbiology with Diseases by Body System (5th Edition)
- A Review Consider the charged disks in Problem 72 (Fig. P26.72). Find an expression for the electric field at point A between the disks on the x axis. Approximate any square roots to three significant figures.arrow_forwardProblems 72, 73, and 74 are grouped. 72. A Figure P26.72 shows a source consisting of two identical parallel disks of radius R. The x axis runs through the center of each disk. Each disk carries an excess charge uniformly distributed on its surface. The disk on the left has a total positive charge Q, and the disk on the right has a total negative charge Q. The distance between the disks is 3R, and point A is 2R from the positively charged disk. Find an expression for the electric potential at point A between the disks on the x axis. Approximate any square roots to three significant figures. FIGURE P26.72 Problems 72, 73, and 74.arrow_forward(a) How much charge can be placed on a capacitor with air between the plates before it breaks down if the area of each plate is 5.00 cm2? (b) Find the maximum charge if polystyrene is used between the plates instead of air. Assume the dielectric strength of air is 3.00 106 V/m and that of polystyrene is 24.0 106 V/m.arrow_forward
- Some cell walls in the human body have a layer of negative charge on the inside surface. Suppose that the surface charge densities are 0.50103C/m2 the cell wall is 5.0109m thick, and the cell wall material has a dielectric constant of = 5.4. (a) Find the magnitude of the electric field in the wall between two charge layers, (b) Find the potential difference between the inside and the outside of the cell. Which is at higher potential? (c) A typical cell in die human body has volume 1016m3 . Estimate the total electrical field energy stored in the wall of a cell of this size when assuming that the cell is spherical. (Hint: Calculate the volume of the cell wall.)arrow_forwardFour capacitors are connected as shown in Figure P25.11. (a) Find the equivalent capacitance between points a and b. (b) Calculate the charge on each capacitor, taking Vab = 15.0 V. Figure P25.11arrow_forwardA parallel-plate capacitor has charge of magnitude 9.00F on each plate and capacitance 3.00F when there is air between the plates. The plates are separated by 2.00 mm. With the charge on the plates kept constant, a dielectric with =5 . is inserted between the plates, completely filling the volume between the plates, (a) What is the potential difference between the plates of the capacitor, before and after the dielectric has been inserted? (b) What is the electrical field at the point midway between the plates before and after the dielectric is inserted?arrow_forward
- Earth can be considered as a spherical capacitor with two plates, where the negative plate is the surface of Earth and the positive plate is the bottom of the ionosphere, which is located at an altitude of approximately 70 km. The potential difference between Earth’s surface and the ionosphere is about 350,000 V. (a) Calculate the capacitance of this system, (b) Find the total charge on this capacitor, (c) Find the energy stored in this system.arrow_forwardUnreasonable Results (a) A certain parallel plate capacitor has plates of area 4.00 m2 separated by 0.0100 mm of nylon, and stores 0.170 C of charge. What is the applied voltage? (b) What is unreasonable about this result? (c) Which assumptions are responsible or inconsistent?arrow_forwardA capacitor has parallel plates of area 12 cm2 separated by 2.0 mm. The space between the plates is filled with polystyrene, (a) Find the maximum permissible voltage across the capacitor to avoid dielectric breakdown, (b) When the voltage equals the value found in part (a), find the surface charge density on the surface of the dielectric.arrow_forward
- Electronic flash units for cameras contain a capacitor for storing the energy used to produce the flash. In one such unit the flash lasts for 1/675 fraction of a second with an average light power output of 270 kW. (a) If the conversion of electrical energy to light is 95% efficient (because the rest of the energy goes to thermal energy), how much energy must be stored in the capacitor for one flash? (b) The capacitor has a potential difference between its plates of 125 V when the stored energy equals the value stored in part (a). What is the capacitance?arrow_forwardA long thin wire is used in laser printers to charge the photoreceptor before exposure to light. This is done by applying a large potential difference between the wire and the photoreceptor. a. Use Equation 26.23, V(r)=20lnRr to determine a relationship between the electric potential V and the magnitude of the electric field E at a distance r from the center of the wire of radius R (r R). b. Determine the electric potential at a distance of 2.0 mm from the surface of a wire of radius R = 0.80 mm that will produce an electric field of 1.8 106 V/m at that point.arrow_forwardFour capacitors are connected as shown in Figure P16.48. (a) Find the equivalent capacitance between points a and b. (b) Calculate the charge on each capacitor, taking Vab = 15.0 V. Figure P16.48arrow_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
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning