Answer / prmdptl2009

induced emf is produed due to the change in flux, since in
normal case in dc there is not any change in flux thats
why emf can not be induced in the coil.

Answer / atul

as we know emf is indused only if there is change in flux
and it is propotional to rate of change of flux.since a.c.
is alternating so flux changes hence emf is induced.on the
other hand dc is constant so flux is constant and hence
rate of change of flux is zero so no emf induced.
emf=-d(flux)/dt.
flux=constant in d.c

Answer / yogan

no

Answer / tarun aggarwal

no induction occur only when ac supply is there. in d.c no
inction is there

Answer / john h

actually voltage through a conductor creates a magnetic
field in both cases AC's field are constantly building and
falling. A DC's voltage creates a constant magnetic field.
is the principle of electro magnet fields. A current is
induced in conductor as it cuts lines of flux. you run a DC
or AC though a coil of wire you still get a Electro
magnetic field.

If you place a peice of paper on your coil with some iron
filings and lightly agitate the paper the iron will display
your created lined of flux.

If you mean Cemf or Counter EMF then no dc will not produce
this. That requires AC. So the change in voltages AC
creates causes the building and colapsing of EMF to occur
as the lines of flux move through a conductor a current is
induced in a opposite direction to oppose current flow
creating your CEMF. which is why a inductor(a coil of wire)
causes a a 90 degree lag in wave forms.

If you would like to see this try putting a coil of wire
around some iron and place it close to a CRT TV. it
distorts the colors and picture with this ELECTROMAGNETIC
FIELD. do not do this to a TV you actually use it can
damage it. some CRT TVs and computer monitors may be
shielded from EMF.

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