Concept explainers
A parallel-plate capacitor has plates of area 10cm2 separated by a 0.10-nun layer of glass insulation with resistivity ρ = 1.2 × 1013 Ω·m and dielectric constant κ = 5.6. Because of the finite resistivity, charge leaks through the insulation, (a) How can such a leaky capacitor be represented in a circuit diagram? (b) Find the time constant for this capacitor to discharge through its insulation, and show that it depends only on the properties of the insulating material and not on its dimensions.
Want to see the full answer?
Check out a sample textbook solutionChapter 25 Solutions
Essential University Physics, Volume 1 and Volume 2 - With Access
Additional Science Textbook Solutions
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
University Physics (14th Edition)
The Cosmic Perspective (8th Edition)
Essential University Physics: Volume 1 (3rd Edition)
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
Cosmic Perspective Fundamentals
- The timing device in an automobile's intermittent wiper system is based on an RC rime constant and utilizes a 0.500F capacitor and a variable resistor. Over whatrange must R be made to vary to achieve time constants from 2.00 to 15.0 s?arrow_forwardAn ECG monitor must have an KC time constant lessthan 1.00102s to be able to measure variations involtage oversmall time intervals, (a) If the resistance of the circuit (duemostly to that of the patient's chest) is 1.00kTwhat is the maximum capacitance of the circuit?(b) Would It be difficult in practice to limit the capacitance to less than the value found in (a)?arrow_forwardThe student engineer of a campus radio station wishes to verify the effectiveness of the lightning rod on the antenna mast (Fig. P21.71). The unknown resistance Rx is between points C and E. Point E is a true ground, but it is inaccessible for direct measurement because this stratum is several meters below the Earths surface. Two identical rods are driven into the ground at A and B, introducing an unknown resistance Ry. The procedure is as follows. Measure resistance R1 between points A and B, then connect A and B with a heavy conducting wire and measure resistance R2 between points A and C. (a) Derive an equation for Rx in terms of the observable resistances, R1 and R2. (b) A satisfactory ground resistance would be Rx 2.00 . Is the grounding of the station adequate if measurements give R1 = 13.0 and R2 = 6.00 ? Explain. Figure P21.71arrow_forward
- An uncharged capacitor with C = 33 μF and a resistor with R = 65 Ω are connected in series with a battery of ε = 1.5 V. Express the time constant τ in terms of R and C and use it to calculate the numerical value of τ in microseconds. Express the maximum charge Q on the capacitor in terms of C and ε and use it to calculate the numerical value of Q in microcoulombs.arrow_forwardConsider an initially uncharged capacitor in an RC circuit. The resistance is 20,000 Ohms and the capacitance is 500 x10• F. If the source potential being used to charge the capacitor is 15 V, how long after charging begins will the power delivered to the resistor be 25 % of its maximum value?arrow_forwardA Christmas light is made to flash via the discharge of a capacitor. The effective duration of the flash is 0.21 s (which you can assume is the time constant of the capacitor), during which it produces an average 35 mW from an average voltage of 2.85 V. What is the resistance, in ohms, of the light?arrow_forward
- When charging a capacitor in series with a resistor, using a 10 V emf source, what would you expect the voltage of the capacitor to be at an initial time of t = τ ? a. 3.68 V b. 0.368 V c. 6.32 V d. 10 V e. 0.632 Varrow_forwardUsing the exact exponential treatment, find how much time is required to discharge a 250-μF capacitor through a 500-Ω resistor down to 1.00% of its original voltage.arrow_forwardA student performs a lab where the voltagedrop across a resistor is measured as a functionof current. Plot a graph from the values givenin the following table, and determine theresistance of the circuit. Current, I (mA) Potential Difference, Current, I (mA)V (V)0.00 0.00200 9.00400 16.0600 24.0800 31.01000 40.0arrow_forward
- A 3.00 M resistor and a 1.00 mF capacitor are connected in series with an ideal battery of emf e= 4.00 V.At 1.00 s after the connection is made, what is the rate at which (a) the charge of the capacitor is increasing, (b) energy is being stored in the capacitor, (c) thermal energy is appearing in the resistor, and (d) energy is being delivered by the battery?arrow_forwardAn uncharged capacitor and a resistor are connected in seriesto a source of emf. If ε = 9.00 V, C = 20.0 µF, and R = 1.00 x102 Ω, find (a) the time constant of the circuit, (b) the maximumcharge on the capacitor, and (c) the charge on thecapacitor after one time constant.arrow_forwardA capacitor that is initially uncharged is connected in series with a resistor and an emf source with EEEMF = 110 VV and negligible internal resistance. Just after the circuit is completed, the current through the resistor is 6.6×10−5 AA. The time constant for the circuit is 4.3 s.What is the resistance of the resistor?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