Taking the loop as shown in 000000000 lo ooO Figure, we apply ampere's law to ∮B=A(②∑1+Lm A∑H+;∑m USing j=4-A nl=(u-I)nl →∑m==∑=心-∑• P  B  0 Taking the loop as shown in I Figure, we apply Ampere’s law to it: B l ( I I ) = + m  d    =  +  m  I  I Using j nI ( )nI s = r − − =       I =  ( −)I = I − I  m  r  