(a) Use the Bio-Savart law to determine the magnetic field due to conduction current outside the plates (refer to Fig) at points `6.5cm,12cm` and `15cm` from the wire. Do the answer match with those in Ex. ? Explain.
(b) If the conduction wire has a radius of 1.0mm, what is the maximum value of magnetic field due to the conduction current? [When you compare the answer to Ex.(b) and 6(b), you will appreciate why it is not easy to notice magnetic field due to the displacement current].
(c) Suppose the thin wire in Fig. is replaced by rods each of radius `12cm` (i.e. we now have two long cylinder rods separated by a small gap). Will magnetic field configurations for `r gt R` be identical for the regions between the plates and outside the plates?

Explanation

(a) Using Biot-Savart law, mangetic
field induction at a point outside a straight current
carrying wire is given by
`B=(mu_0I_D)/(2pir)`
Now, since `I=I_D`, this formula is the same as
in for `r gt R`. Therefore , for `r=12cm` and
`15 cm`, answers are the same as in For
`r=6.5 cm (r lt R)`, the two formulae differ. Here
`B=4.6xx10^-7T`, greater than B is
(b) B is maximum at the surface of the wire,
`B=(mu_0I)/(2pir)=(4pixx10^-7)/(2pixx10^-3)=3.0xx10^-6T`
[Here, `r=1.0mm=10^-3m]`
This is much greater than the maximum value
of B in Due to this reason, it is not easy to
notice magnetic field due to displacement current.
(c) Yes, since`I=I_D`, magnetic field
Configuration are identical for `r gt R`.