OpenStax College Physics, Chapter 19, Problem 15 (Problems & Exercises)
My professor gave us the equation deltaV=-E*delta d, is this the same as V=Ed? I thought i was supposed to use the negative sign, so my answer ended up being wrong
Hi mesmes, in a question like this "what is the potential difference" it's common to not care about the negative sign. Strictly speaking is best, but the is understood in this context. We're always measuring differences. Voltage, like any mechanical potential energy, is always a difference compared to something else. In this case it's the difference between the two plates.
As a thought experiment to understand where the negative comes from, electric field causes the kinetic energy of an initially stationary positive test charge to increase by accelerating it in the direction of the field. This increase in kinetic energy comes with an equal reduction in potential energy. Electric field therefore is pointing in the direction of decreasing potential energy. The negative sign is meant to indicate this.
Can someone explain the exponents to me?