Three identical long straight conductors X, Y and Z pass vertically through a…
MATHEMATICS · Subjective · ISC · Physics · Magnetic Effects of Current and Magnetism · Ampere's circuital law
Problem
Three identical long straight conductors X, Y and Z pass vertically through a laboratory bench at three different locations. The currents through the conductors are 2 A, 4 A and 6 A respectively, all flowing upward. Points P, Q and R are located in the horizontal plane of the bench such that point P is 2 cm from conductor X, point Q is 4 cm from conductor Y and point R is 6 cm from conductor Z.
(i) Without using any numerical constant associated with magnetic permeability, calculate the ratio of magnetic field strengths at points P : Q : R.
(ii) If point P is moved directly away from conductor X so that the magnetic field strength at the new location equals that at point Q, determine the required distance of point P from conductor X.
(iii) Explain why your answer in part (ii) is independent of the actual value of the magnetic field strength at point Q.