Question { CMC, 2325 }

How one can say about a device (e.g: a light holder
contains 20 or 30 L.E.Ds which glows when power supply is
off, from which source they are getting the supply.....
battery or capacitor) without removing and opening up its
case ?

Answer

capacitor only for short time operation.if u want to glow long term battery is preferable.

Question { IOCL, 2192 }

where this neutral connection goes after returning from the
load(home ,factory,industries).Is it grounded at the
transformer side or atthe generator side .If it is grounded
then we also ground the earth connection.is there any
problem with this.

Answer

Transformer secondary side neutral is earthed.if unbalanced load condition residual return current only goes to earth it's a safest one actually.In basic ground is the very low impedance path compare to your earth rod.current always choose low resistive path.so it's not possible to return feed current flow from ground to equipment.