If a long hollow copper pipe carries a current, then magnetic field is

1.	If a long hollow copper pipe carries a current, then magnetic field is produced:
Answer» inside the pipe only outside the pipe only both inside and outside the pipe no where Solution :According to Ampere's circuital law, `B(2pir)=mu_(0)xx0` or `B=0` So, inside a hollow metallic (copper) pipe carrying CURRENT, the magnetic field is zero. But for external points, the whole current BEHAVES as if were concentrated at the axis only, so outside `B_(0)=(mu_(0)i)/(2pir)` Then, the magnetic field is produced outside the pipe only

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