Concept explainers
Cheap resistors are fabricated by depositing a thin layer of carbon onto a non-conducting cylindrical substrate (see Figure P2.44). If such a cylinder has radius a and length d, determine the thickness of the film required for a resistance R if:
Neglect the end surfaces of the cylinder and assume that the thickness is much smaller than the radius.
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
Principles and Applications of Electrical Engineering
- Two long straight current-carrying wires are lined up parallel to one another in vacuum at a distancedCurrents of I1 and flow I2 through the wires, both in the same direction generating the field of B Delta f at a midpoint between themWrite down an expression for BM in terms of the currents running in each of the wires Assume vacuum permeability u= 1arrow_forwardA copper wire 100 m long must experience avoltage drop of less than 1.5 V when a current of 2.5 A passesthrough it. Given that copper has an electrical conductivity of6.0E7 /(Ὠ-m), compute the minimum diameter of the wire.arrow_forwarda rod of semiconducting meterial of length L = 2 m and cross-sectioanal area A=5mm2 lies along the x axis between x=0 and x=L. the meterial obeys Ohm's law, and its resistivity varies along the rod according to p=p0 (1-(x2/L2)) where p0=4,5 * 10-4 ohm*m. the end of the rod at x=0 is at a potential V0= 30 V greater than the end at x = L. a)what is the total resistance, in units of ohm, of the rod ? b)what is the current, in units of miliamperes in the rod? c)what is the electric potential, in units of Volt in the rod at x=L/2 ? d)what is the electric field magnitude E, in units of V/m, in the rod at x=L/2 ?arrow_forward
- A copper wire of 3mm diameter with conductivity of 5.8 * 10 '(22.m)', and electron mobility of 0.0032 m V.Sec. is subjected to an electric field of 30mVm. Find (a) the charge density of free electrons, (b) current flowing in the wire, (e) the electron draft velocity.arrow_forwardConductors A conducting wire is 2 mm in radius and 100 m in length. When a dc voltage of 9 Vis applied to the wire, it results in a current of 0.3 A. Find: The E-field in the wire, The conductivity of the wire.arrow_forwardOn a square wireframe with side length a in empty space, there is a linear charge density ρl. Calculate a·ρl numerically by finding a solution for the values of a and ρl required for the potential at the center of this square frame to be V = 0 [Volt].arrow_forward
- According to the figure below, wire section 1 of diameter D1 = 8 R and wire section 2 of diameter D2= 4R connected by a tapered section. The wire is copper, its resistivity uniformly distributed across any cross-section area through the wire's width. The electric potential change V along the length L = 4 m shown in section 2 is 20 µV. The number of charge carriers per unit volume is 8.49 x 1028 m3.What is the drift speed of the conduction electrons in section. 1.69 x 10-8 Qm and carriers a current. Assume that the current isarrow_forward9. Write an equation to obtain the potential difference at point a with respect to point b, Vab? 10. What is the potential difference at point a with respect to point b, Vab?arrow_forward] A copper wire of 3mm diameter with conductivity of 5.8 * 10 '(22.m)', and electron mobility of 0.0032 m² V.Sec. is subjected to an electric field of 30mVm. Find (a) the charge density of free electrons, (b) current flowing in the wire, (c) the electron draft velocity.arrow_forward
- A) Explain briefly various theories of breakdown in liquid dielectrics. B) What are the requirements of a sphere gap for measurement of high voltages? Discuss the advantages and disadvantages of sphere gap for measurements. C) Determine the Townsend’s first ionization coefficient if a steady current of 500 ?A flows through the plane electrode separated by a distance of 0.4cm when a voltage of 10 kV is applied. A current of 25 ?A flows when the distance of separation is reduced to 0.1 cm and the field is kept constant at the previous value. Find also the value of γ if the breakdown took place when the gap distance was changed to 0.7 carrow_forwardOn a square wireframe with side length a in empty space, there is a linear charge density ρl.Calculate a · ρl numerically by finding a solution for the values of a and ρl required for the potential at the center of this square frame to be V = 4 ke [Volts].arrow_forwardConsider a conductor plate carrying a current I as shown in the figure. Current flows in the negative direction. It is also known that a conductor has a charge-carrying density of n with 1 particle carrying a charge q . This conductor plate is then placed on the a region with an external magnetic B field in the z direction . Determine the potential difference across the conductors! State the answer in terms of B, n, q, I, B, and d! (Assume positive charge carrier) *This potential, which is often referred to as the Hall potential V_H, is commonly measured in experiments to determine the properties of a material. However, there are other quantities that are also measured namely the Hall coefficient R_H. In ordinary metals, the relationship between R_H and V_H is as following (equation in figure)arrow_forward
- Introductory Circuit Analysis (13th Edition)Electrical EngineeringISBN:9780133923605Author:Robert L. BoylestadPublisher:PEARSONDelmar's Standard Textbook Of ElectricityElectrical EngineeringISBN:9781337900348Author:Stephen L. HermanPublisher:Cengage LearningProgrammable Logic ControllersElectrical EngineeringISBN:9780073373843Author:Frank D. PetruzellaPublisher:McGraw-Hill Education
- Fundamentals of Electric CircuitsElectrical EngineeringISBN:9780078028229Author:Charles K Alexander, Matthew SadikuPublisher:McGraw-Hill EducationElectric Circuits. (11th Edition)Electrical EngineeringISBN:9780134746968Author:James W. Nilsson, Susan RiedelPublisher:PEARSONEngineering ElectromagneticsElectrical EngineeringISBN:9780078028151Author:Hayt, William H. (william Hart), Jr, BUCK, John A.Publisher:Mcgraw-hill Education,