An air-filled parallel-plate capacitor has a capacitance of 1 pF. A wax dielectric is then inserted, completely filling the space between the plates. As a result, the capacitance becomes 2 pF. The dielectric constant of the wax is: 4.0 0.25 0.50 2.0

An air-filled parallel-plate capacitor has a capacitance of 1 pF. A wax dielectric is then inserted, completely filling the space between the plates. As a result, the capacitance becomes 2 pF. The dielectric constant of the wax is: 4.0 0.25 0.50 2.0

University Physics Volume 2

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter8: Capacitance

Section: Chapter Questions

Problem 82CP: A parallel-plate capacitor is filled with two dielectrics, as shown below. When the plate area is A...

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A parallel-plate capacitor of plate separation d is charged to a potential difference V0. A dielectric slab of thickness d and dielectric constant is introduced between the plates while the battery remains connected to the plates. (a) Show that the ratio of energy stored after the dielectric is introduced to the energy stored in the empty capacitor is U/U0 = . (b) Give a physical explanation for this increase in stored energy. (c) What happens to the charge on the capacitor? Note: This situation is not the same as in Example 25.5, in which the battery was removed from the circuit before the dielectric was introduced.
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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?
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