If we isolate wire with thin wire and assuming that no heat rejected by wire then does electromagnet work. If it work then it violate conservation of energy .
1
-
2$\begingroup$ Why do you think it violates conservation of energy? $\endgroup$– probably_someoneCommented Jun 4, 2020 at 3:12
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
2
No, it doesn't, even in the case of a perfect wire with no heat loss. Here is why.
To create a magnetic field requires the expenditure of work. In the case of a coil of wire, the work to create the field is done by the time integral of (voltage x current). Once the current has achieved steady state, that current is then required to sustain the field. When the electrical power to the coil is shut off, the field collapses and induces an amount of current flow in the wire. The electrical energy returned to the coil in this way equals that which it took to create the field in the first place, and energy is conserved.
answered Jun 4, 2020 at 3:35
-
$\begingroup$ If no, then there must be any relation between heat and magnet what do u think $\endgroup$ Commented Jun 5, 2020 at 12:53
-
$\begingroup$ I do not know what you mean... $\endgroup$ Commented Jun 5, 2020 at 14:49