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 parallelplate, airfilled 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
0722 
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
1134 
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?
095 
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 4.80µF capacitor.
0172 
Several 0.25µF 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
1158 
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.
2164 
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
41108 
Three capacitors having capacitances of 8.4, 8.4, and 4.2µF are connected in series across a 36V potential difference. (a) What is the charge on the 4.2µF 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
1502 
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
1559 
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.
0122