A very long wire carries a uniform linear charge density A. Using a voltmeter to measure potential difference, you find that when one probe of the meter is placed 2.50 cm from the wire and the other probe is 1.00 cm farther from the wire, the meter reads 575 V.
(a) What is A?
(b) If you now place one probe at 3.50 cm from the wire and the other probe is 1.00 cm farther away, will the voltmeter read 575 V? If not, will it read more or less than 575 V? Why?
(c) If you place both probes 3.50 cm from the wire but 17.0 cm from each other, what will the voltmeter read?