A person holds a small compass near a long, straight wire that is carrying a cur

Question

A person holds a small compass near a long, straight wire that is carrying a current, but detects no deflection of the compass needle and therefore concludes that there is no magnetic field near the wire. which of the following statement is most likely the assumption made by the person to arrive at this conclusion?

A. The wire is carrying a current
B. Any magnetic field due to a current in a wire is much greater than the earth'd magnetic field.
C. The site is at least several meters long
D. There is no deflection of the compass needle near the wire
E. Current has been flowing through the wire for an extended period of time

Please explain why & why not on each parts it would be greatly appreciated Thank you.

Explanation / Answer

C, because any wire has resistance to current flow, and the current might have been completely damped by the time it got to the persons position.
a. is not an assumption because it is the given. He might assume however that he was misled about current being in the wire
b. is also backwards. He might assume that the earth has a greater field than the one produced by the current in the wire, so it is masked.
d. Is an observation, not an assumption
e. how much time current flows has no effect on the strength of a magnetic field

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.