An equilateral triangle with sides 89 m has charges +2 µC, −2 µC, and −10.2 µC at its vertices and charge +20.4 µC at the midpoint on its side between the vertices with charges +2 µC and −2 µC. 89 m 44.5 m 44.5 m 89 m +2 µC −2 µC −10.2 µC P +20.4 µC What is the magnitude of the x-component of the electric field at P, the point forming a second equilateral triangle with +2 µC and −2 µC? The permittivity of free space is 8.85419 × 10−12 C 2 /N/m2 . Answer in units of N/C.

Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

Why is the use of carbon-14 limited