A long straight vertical wire carries a current of 5 A upward
MATHEMATICS · Single correct · ISC · Physics · Magnetic Effects of Current and Magnetism · Ampere's circuital law
Problem
A long straight vertical wire carries a current of 5 A upward. Point A is 2 cm from the wire, and point B is 4 cm from the wire, both lying in the same horizontal plane. What is the ratio BA:BB of the magnitudes of the magnetic fields at A and B?
(a) 4:1
(b) 2:1
(c) 1:2
(d) 1:1