Showing 131 to 140 of 528 Questions
  • In one type of computer keyboard, each key holds a small metal plate that serves as one plate of a parallel-plate, air-filled capacitor. When the key is depressed, the plate separation decreases and the capacitance increases. Electronic circuitry detects the change in capacitance and thus detects that the key has been pressed. In one part

  • Consider a cylindrical capacitor like that shown in Fig. Let d = rb - rc. be the spacing between the inner and outer conductors. (a) Let the radii of the two conductors be only slightly different, so that d « ra . Show that the result derived in Example 24.4 (Section 24.1) for the capacitance of a cylindrical. Capacitor then reduces to

  • In Fig let C1 = 9.0µF, C2 = 4.0µF, and Vab = 28V. Suppose the charged capacitors are disconnected from the source and from each other, and then reconnected to each other with plates of opposite sign together. By how much does the energy of the system decrease?

  • For the capacitor network shown in Fig, the potential difference across ab is 12.0 V. Find (a) The total energy stored in this network and (b) The energy stored in the 4.80-µF capacitor.

  • Several 0.25-µF capacitors are available. The voltage across each is not to exceed 600 V. You need to make a capacitor with capacitance 0.25 µF to be connected across a potential difference of 960 V. (a) Show in a diagram how an equivalent capacitor with the desired properties can be obtained. (b) No dielectric is a perfect insulator th

  • In Fig, C1 = C5 = 8.4µF and C2 = C3 = C6 = 4.2µF. The applied potential is Vab = 220 V. (a) What is the equivalent capacitance of the network between points a and b? (b) Calculate the charge on each capacitor and the potential difference across each capacitor.

  • The capacitors in Fig. are initially uncharged and are connected, as in the diagram, with switch S open. The applied potential difference is Vab = +210 V.(a) What is the potential difference Vcd? (b) What is the potential difference across each capacitor after switch S is closed? (c) How much charge flowed through the switch when it was c

  • Three capacitors having capacitances of 8.4, 8.4, and 4.2µF are connected in series across a 36-V potential difference. (a) What is the charge on the 4.2-µF capacitor? (b) What is the total energy stored in all three capacitors? (c) The capacitors are disconnected from the potential difference without allowing them to discharge. They ar

  • Capacitance of a Thundercloud The charge center of a thundercloud, drifting 3.0 km above the earth's surface, contains 20 C of negative charge. Assuming the charge center has a radius of 1.0 km, and modeling the charge center and the earth's surface as parallel plates, calculate: (a) The capacitance of the system; (b) The potential differ

  • In Fig, each capacitance C1 is 6.9 µF, and each capacitance C2 is 4.6 µF. (a) Compute the equivalent capacitance of the network between points a and b. (b) Compute the charge on each of the three capacitors nearest a and b when Vab = 420V. (c) With 420V across a and b, compute Vcd.