Verified answer

The electric potential at a point in an electric field measures the Elec.PE a charge will have at that point in J/C (ie 0V = 0 Joules per Coulomb, 100V = 100J/C)

The actual amount of EPE at a point = q (C) x Potential (J/C = V)

By moving from a point at 0V to a point at 100V the EPE changes by 100 J/C

.. so for - 25.0^-6C the EPE change (∆PE) = 100J/C x - 25.0^-6C = (-) 2.50^-4 J

Because there are electric forces acting on the charged sphere, work will need to be done moving it .. and the work done (in J) = Change in EPE (in J)

So the WD ►= - 2.50^-4 J

It is actually a EPE loss (-) .. so a negative amount of work is needed as the sphere is naturally attracted to the +100V point and doesn't have to be 'driven' there by an external force. It is the same for mass in a gravitational field .. when a mass naturally falls it loses GPE, when it is 'driven' higher it gains GPE.

∆ means 'change in'

In this case ∆W is likely to mean 'change in' the Elec.PE amount (W = EPE) .. it is misleading in that it can be read as change in work.

some sturdy solutions the following between some obtuse or perhaps incorrect ones. certain to the precise wording of the question: the electric powered field is going out from the cost, and does no longer loop again upon itself. at the same time as the magnetic field itself is created via shifting electric powered cost (yet no longer the static electric powered field created via a table sure cost!), and continually loops again upon itself. This latter property is represented as actual one of Maxwell's/Heavisides' Equations. The equation in question states that the divergence of a magnetic field is an identical as 0. This describes our contemporary recognize-how that the magnetic field or lines do no longer originate from a factor cost, compared to an electric powered field. And that, again, the magnetic field itself has no line ends, because the lines (or field) continually varieties a continuous loop again upon itself.

ηC? Did you mean μC or nC?