Answer:
Option C
Explanation:
According to question , magnetic
permeability of the rod is given by , μr=BB0
where, B= magnetic field without iron rod
B0 = magnetic field after insertion of iron rod
so, μr=B2000Am−1
(∵B.A=ϕ⇒B=ϕA=6×10−4Wb3×10−4m2=2Wbm−2)
So, μr=22000=10−3