A capacitor is constructed from two square, metal- +Q lic plates of sides l and separation d. Charges and -Q are placed on the plates, and the power sup- ply is then removed. A material of dielectric constant k is inserted a distance x into the capacitor as shown in Figure P26.78. Assume d is much smaller than x. (a) Find the equivalent capacitance of the device. (b) Calculate the energy stored in the capacitor. (c) Find the direction and magnitude of the force exerted by the plates on the dielectric. (d) Obtain a numerical value for the force when x = €/2, assuming l = 5.00 cm, d = 2.00 mm, the dielectric is glass (K = 4.50), and the capacitor was charged to 2.00 × 10³ V before the dielectric was inserted. Suggestion: The system can be considered as two capacitors connected in parallel. %3D %3D + ++Q -x- d к

A capacitor is constructed from two square, metal- +Q lic plates of sides l and separation d. Charges and -Q are placed on the plates, and the power sup- ply is then removed. A material of dielectric constant k is inserted a distance x into the capacitor as shown in Figure P26.78. Assume d is much smaller than x. (a) Find the equivalent capacitance of the device. (b) Calculate the energy stored in the capacitor. (c) Find the direction and magnitude of the force exerted by the plates on the dielectric. (d) Obtain a numerical value for the force when x = €/2, assuming l = 5.00 cm, d = 2.00 mm, the dielectric is glass (K = 4.50), and the capacitor was charged to 2.00 × 10³ V before the dielectric was inserted. Suggestion: The system can be considered as two capacitors connected in parallel. %3D %3D + ++Q -x- d к

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter20: Electric Potential And Capacitance

Section: Chapter Questions

Problem 38P: A variable air capacitor used in a radio tuning circuit is made of N semicircular plates, each of...

See similar textbooks

Similar questions

What If? The two capacitors of Problem 13 (C1 = 5.00 F and C2 = 12.0 F) are now connected in series and to a 9.00-Y battery. Find (a) the equivalent capacitance of the combination. (b) the potential difference across each capacitor, and (c) the charge on each capacitor.
(a) Find the equivalent capacitance between points a and b for the group of capacitors connected as shown in Figure P16.46 if C1 = 5.00 F, C2 = 10.00 F, and C3 = 2.00 F. (b) If the potential between points a and b is 60.0 V, what charge is stored on C5? Figure P16.46
When a Leyden jar is charged by a hand generator (Fig. 27.1, page 828), the work done by the person turning the crank is stored as electric potential energy in the jar. When a capacitor is charged by a battery, where does the electric potential energy come from?
A variable air capacitor used in a radio tuning circuit is made of N semicircular plates, each of radius R and positioned a distance d from its neighbors, to which it is electrically connected. As shown in Figure P20.38, a second identical set of plates is enmeshed with the first set. Each plate in the second set is halfway between two plates of the first set. The second set can rotate as a unit. Determine the capacitance as a function of the angle of rotation , where = 0 corresponds to the maximum capacitance. Figure P20.38
(a) Find the equivalent capacitance between points a and b for the group of capacitors connected as shown in Figure P16.46 if C1 = 5.00 F, C2 = 10.00 F, and C3 = 2.00 F. (b) If the potential between points a and b is 60.0 V, what charge is stored on C5? Figure P16.46
An electronics technician wishes to construct a parallel plate capacitor using rutile ( = 100) as the dielectric. The area of the plates is 1.00 cm2. What is the capacitance if the rutile thickness is 1.00 mm? (a) 88.5 pF (b) 177 pF (c) 8.85 F (d) 100 F (e) 35.4 F
An infinite number of charges with q = 2.0 C are placed along the x axis at x = 1.0 m, x = 2.0 m, x = 4.0 m, x = 8.0 m, and so on, as shown in Figure P26.78. Determine the electric potential at the point x = 0 due to this set of charges. Hint: Use the mathematical formula for a geometric series, 1+r+r2+r3+r4+=11r FIGURE P26.78
A parallel-plate capacitor has plates of area A = 7.00 102 m2 separated by distance d = 2.00 104 m. (a) Calculate the capacitance if the space between the plates is filled with air. What is the capacitance if the space is filled half with air and half with a dielectric of constant = 3.70 as in (b) Figure P16.56a, and (c) Figure P16.56b? (Hint: In (b) and (c), one of the capacitors is a parallel combination and the other is a series combination.) Figure P16.56
A parallel-plate capacitor is charged and then is disconnected from the battery. By what factor does the stored energy change when the plate separation is then doubled? (a) It becomes four times larger. (b) It becomes two times larger. (c) It stays the same. (d) It becomes one-half as large. (e) It becomes one-fourth as large.
(a) Find the equivalent capacitance between points a and b for the group of capacitors connected as shown in Figure P25.12 (page 686). Take C1 = 5.00 F, C2 = 10.0 F, and C3 = 2.00 F. (b) What charge is stored on C3 if the potential difference between points a and b is 60.0 V? Figure P25.12
For the system of capacitors shown in Figure P16.41, find (a) the equivalent capacitance of the system, (b) the charge on each capacitor, and (c) the potential difference across each capacitor. Figure P16.41 Problems 41 and 60.
A parallel-plate capacitor with capacitance C0 stores charge of magnitude Q0 on plates of area A0 separated by distance d0. The potential difference across the plates is V0. If the capacitor is attached to a battery and the charge is doubled to 2Q0, what are the ratios (a) Cnew/C0 and (b) Vnew/V0? A second capacitor is identical to the first capacitor except the plate area is doubled to 2A0. If given a charge of Q0, what are the ratios (c) Cnew/C0 and (d) Vnew/V0? A third capacitor is identical to the first capacitor, except the distance between the plates is doubled to 2d0. If the third capacitor is then given a charge of Q0, what are the ratios (e) Cnew/C0 and (f) Vnew/V0?