Are these the same thing? Or does the electrical potential difference refer to the voltage source only?
I don't think you should try to nail down these terms too rigidly. Suppose you have a battery with a potential difference of 1.5v across its terminals, and you connect the battery along with other components to form the branch of a circuit. The contribution the battery makes to the potential difference across that branch can be regarded as a voltage drop or a voltage rise, depending on the orientation of the battery.OK. So if we are given a simple circuit with a battery and three resistors, a potential difference could be from the negative to the positive on a battery or across each resistor (in either direction) and a voltage drop will have nothing to do with the battery, but can be taken in only one direction across resistors. Correct?
I am probably beyond the stage where I can do much harm to physics or wreak the harm done to me."Then the difference between potential and emf has always baffled me"..... I hope that, for the good of physics, you are not confused about the difference between emf and pd !!. For the general public what is wrong with 'DANGER KEEP OUT' ... no physics knowledge required to understand this message !!
At school we were told 'amperage' was very bad but no one turned a hair at 'voltage' - that was the term used in lessons mostly (capacitors were still condensers then mynah mynah). I am sure you will find old textbooks, especially for electricians and technicians, and engineering journals full of this terminology, devices like voltage stabilisers, laws like KCL and KVL not KPL, there is even quite a lot of this at this site. And it has always been admitted that emf is not a good term really! Open circuit potential' OTOH is really suggestive and tells you what is meant.I do agree with the reference to 'amperage'....who would ever talk about 'amerage difference'....AMP.and VOLT are units..why refer to 'voltage difference'.....unless you are very confident ...you would never refer to 'amperage difference'...would you ??
What is wrong with'Potential difference in volts' !!!!!
EMF in volts ????
Language gets so confusing..... because we all take shotcuts
I was taught in high school that voltage is potential difference
but what was potential ?
The concept of work done moving against a field just didnt seem to relate .
What clarified it for me was when concept of absolute potential clicked in place -
' the work done in bringing a unit of charge from infinity to wherever you are.....'
i could just imagine myself traveling from Alpha Centauri to Miami Central High School with a bucketful of charge and tabulating the force encountered every centimeter...
Nobody is going to go out to infinity and hold a voltmeter lead there for you to make that measurement
we have to settle for measuring the difference in absolute potentials between two points closer to us, and we call that voltage,
We do not know the absolute potential of either point and cannot measure it
but their difference is readily measured by a voltmeter with two leads of finite length.
'Difference in absolute potentials' shortens to potential difference , aka 'voltage'.
In my world, voltage is always a potential difference between two points.
We get sloppy in our communication and do not always define those two points,
one of them is usually a 'circuit common' of some sort which is often called 'ground'
though it may be or may not be connected to earth .
If that potential difference exists because of current flowing through a resistance, that's a voltage drop.
If that potential difference exists because of, let's say the chemistry going on inside a battery, that's not a voltage drop it's just a voltage (or maybe a voltage rise).
Sorry to be so verbose
but the price of clear communication is excruciating attention to language.
Hope mine was clear .. exaggeration is often a useful tool.