A current of i ampere flows along an infinitely long straight thin walled tube, then the magnetic induction at any point inside the tube is |
infinite zero $\frac{μ_02i}{4\pi r}$ (tesla) $\frac{μ_0i_0}{4 r}$ (tesla) |
zero |
$ I_{enclosed} = 0$ $\Rightarrow B .2\pi r = \mu_0 I_{enclosed} = 0$ |