So the question is as follows:

"Your mobile HF transceiver draws 22 amperes on transmit. The
manufacturer suggester limiting voltage drop to 0.5 volt and the
vehicle battery is 3 metres(10 feet) away. Given the losses below at
that current, which minimum wire gauge must you use?"


and the options are as follows:

A) Number 8, 0.05 V per metre (0.01 V per foot)
B) Number 12, 0.11 V per metre (0.03 V per foot)
C) Number 10, 0.07 V per metre (0.02 V per foot)
D) Number 14, 0.19 V per metre (0.06 V per foot)


I believe that the answer is option B as it is the highest voltage drop that is below .5 volts for 10 feet of cable. But the answer key states that answer C is correct.

• I take it, if anyone can answer, that the stated drops in the possible answers are per metre for the given load and not just per amp per meter as they would usually be stated in reference guides? - I haven't gone and looked for my guide in the library to check. Commented Sep 13, 2018 at 11:10
• What exam is that? You should tell the professor that voltage drop depends on amperage. The way this is stated gives the impression of voltage drop being independant from current. Especially when you throw a trick like "distance back and forth" while dropping the important part "voltage drop is linear on current" Commented Sep 13, 2018 at 17:20
• @Jeffrey the question states that voltage drop is related to current "Given the losses below at that current", also the exam is for an amature radio license in my country Commented Sep 13, 2018 at 23:17