D6.8. Given the volume charge density p, = -2 x 10’eo/FC/m³ in free space, let V = 0 at x = 0 and let V = 2 V at x = 2.5 mm. At x = 1 mm, find: (a) V; (b) Ex. Ans. 0.302 V; -555 V/m

Estimate the length of conduit to perform the next bends. EMT will be bend using a hand bender. Provide your answer in inches (just the number) using up to 2 decimals. The picture shows two panels connected by a back-to-back 23.5" stubs EMT 3/4" 6.25 ft P

Assuming all terminals are rated 75°C and you have a  #10 AWG THHN/THWN conductors in a conduit and the conduit is run on the roof off a office building where the ambient temperature never rises above 30°C the largest size circuit breaker or fuse permitted to protect these wires is:?

The wording that I am running into with questions such as "The number of conductors required to be installed between three-way and four-way switches is " is confusing.  The text is not expalining this in a way that I am understanding anything other than grounding conductor, which is optional unless I am using a metal box.  So what type of "conductor" is beng discussed?