What Does the Negative Sign in the Electrostatic Potential V Formula Represent?

[ap1993]

See this page:

http://teacher.nsrl.rochester.edu/phy122/Lecture_Notes/Chapter25/Chapter25.html#Heading1"

Why is there a negative sign in the formula for electrostatic potential V?

 

[sophiecentaur]

Potential at a position is defined as the Work Done in bringing a charge (or whatever) from infinity to that position. For an attractive situation (+ and - charges, for instance), the work 'put in' is negative, because you get work out. For a negative charge around an atom or a small mass near a large one, you can look upon it as being in a 'potential well', with the potential at a minimum if and when they 'land'. You can only leave the influence of the attractor if you have more kinetic energy (positive) than the negative potential energy due to position.

 

[tiny-tim]

welcome to pf!

hi ap1993! welcome to pf!

yes, https://www.physicsforums.com/library.php?do=view_item&itemid=269" by a conservative force

eg, in gravity, PE increases when you go up, because the gravitational force is down

(and electric potential = potential energy per charge)

 

[ap1993]

thanks-i got it!

 

[sardar]

The negative sign in the formula for electrostatic potential V is a result of the convention used to define the direction of electric potential. In this convention, the direction of electric potential is defined as the direction in which a positive test charge would move. As we know, electric charges of the same sign repel each other, so a positive test charge would move away from a positive source charge and towards a negative source charge. Therefore, the potential at a point due to a positive source charge is considered to be positive, while the potential at a point due to a negative source charge is considered to be negative. This convention allows for a consistent and standardized way of measuring and comparing electric potentials.