User:Vsnkumar
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in every home there is a tube light along with chock. my doubt is what is the back emf at the time when the supply to the chock is off since at the time of switch on the supply for chock we can calculate the back emf with the inductance value,resistance value,voltage and also we know time constant but iam asking AT THE TIME OF SUPPLY IS OFF SINCE AT THE TIME OF SUPPLY IS OFF, COLLAPSING MAGNETIC FIELD IS VERY VERY FAST AND ITS TIME CONSTANT IS VERY VERY LOWER THEN THE TIME CONSTANT AT THE TIME OF SUPPLY IS GIVEN TO THE CHOCK. IAM ASKING BACK EMF AT THE TIME WHEN THE SUPPLY TO THE CHOCK IS OFF DUE TO THE VERY HIGH RATE OF CHANGE OF COLLAPSING MAGNETIC FIELD.vsnkumar (talk) 13:24, 8 August 2011 (UTC)