How to Get Electric Field from Electric Potential | Physics with Professor Matt Anderson | M20-01

Okay, we understand electric field and electric potential separately, but clearly they are related. Let's look at how we can get the field from the potential.
Physics with Professor Matt Anderson

[@maskedmarvyl4774]

Very nice demonstration, thank you. However, at 5:00, you write the equation V/r=E. Are you using Ohm's law here at this point and assuming the audience understands what you are doing (Voltage V divided by the resistance R equals the current E), or does "r" represent the radius that you drew on your point charge earlier to represent your equipotential surface?

[@fizixx]

You DO see r-hat there, way before that 5 minute time, right? Resistence isn't a vector. So that should be indicating to you that this isn't Ohm's law, and V/r is not current.

[@yoprofmatt]

Great discussion, people. And yes, when you divide voltage by distance you get units of electric field. It gets confusing when we reuse letters like R (resistance) and r (radius). Which physicists do a lot. And then we used greek. Need more letters. Cheers, Dr. A

[@peterwan小P]

I’m sorry professor, but this still doesn’t make sense to me. If it’s a sheet of charge how can its potential be increasing over Z which should be away from the plate and still have negative V below z = 0

[@backspace2811]

V is starting at positive then gets closer to 0 as it gets further from positive sheet of charge