So, the question we posed was:
So, if we create a cell that has (-) negative EMF value, then would the current pass through the circuit or not ?
Give it a thought yourself, then continue to scroll …
Normally, in our school/college we do some calculations, and when the EMF comes out to be negative, we declare the cell as impossible.
The actual thing is:
Who are You to decide the if the cell would have negative or positive EMF?
There is nothing called negative EMF.
If both half cells have equal potential, then EMF would be zero(0).
If half cells have different potential, then EMF would be positive.
But there is negative EMF in calculations …
Yes, negative EMF are there, but only in your calculations.
We would try to explain it like this …
What you have done to create a cell?
You just joined the two half cells with wire. And you did nothing else. So, it was in hands of nature to decide which half cell will act as cathode and which as anode.
By itself, nature will choose the electrode with relatively higher potential to be as cathode.
So if cathode is higher by nature, then
should be guaranteed positive.
So, negative EMF in your calculations only means that
In a cell, you chosen wrong electrode as cathode. Its your fault only.
That’s what happen in your exam calculations is that you are already mark cathode & anode, but if in reality nature favors opposite, then EMF in calculations comes out to be negative.
But current always flows whenever there’s difference in electrode potential.
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