The magnetic induction at a point P which is at a distance of 4cm from a long current-carrying
wire is 10^3T. The field of induction at a distance of 12cm from the current carrying wire will be:
(A) 3.33x10^4T (B) 1.11x10^4T
(C) 3x10^3T (D) 9x10^3T

(all ^ are negative)

1

Answers

2016-01-04T09:03:21+05:30
We know B=10^-7*2I/r where B =magnetic field of a long current carrying conductor
I=amount of current
r=distance from current element
10^-3=10^-7*2*I/4*10^-3
=>I=20 A
again B=10^-7*2*20/12*10^-3=
3.33*10^-4(a)
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