If a conductor (copper wire) is put into an electric filed, will there be a current generated in the conductor (when the two ends of the conductor is closed.) I am thinking there will be only a instant short current. Please suggest and advise. Thanks,
Hi Rui Kou ,
it depends on the field:
If the field is conservative, there will be only a redistribution of the charges (= a short current, as you suspected) when the conductor is brought into the field. A conservative field (curl = 0) equals the static field of a static distribution of electric charges.
If the loop is moved (e. g. rotated) then a small alternating current can flow as long as the movement continues. See for instance "field mill".
If the electric field has a curl component then a current will flow in the conducting loop, provided that at least some of the curl is passing through the loop. Because curl E = -d B / d t, there will be simultaneously a change of the magnetic flux through the loop (induction). If the loop doesn't contain non-linear elements (like diodes) then only an alternating current can flow, of course. (DC would result from an unlimited change of B which is not possible, obviously.)
Hi Rui Kou ,
it depends on the field:
If the field is conservative, there will be only a redistribution of the charges (= a short current, as you suspected) when the conductor is brought into the field. A conservative field (curl = 0) equals the static field of a static distribution of electric charges.
If the loop is moved (e. g. rotated) then a small alternating current can flow as long as the movement continues. See for instance "field mill".
If the electric field has a curl component then a current will flow in the conducting loop, provided that at least some of the curl is passing through the loop. Because curl E = -d B / d t, there will be simultaneously a change of the magnetic flux through the loop (induction). If the loop doesn't contain non-linear elements (like diodes) then only an alternating current can flow, of course. (DC would result from an unlimited change of B which is not possible, obviously.)
Yes, to what Joerg says. I'll just add the short version: magnetic field must be changing to induce current.
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