Electric potential Flashcards
Explain why potential is defined in terms of the work done per unit + charge Calculate the electric potential difference between two points Describe how to find the change in electric potential energy from pd Explain why potential is measured in V
Explain why potential is defined in terms of work done per unit + charge
To move a small positive charge a distance x towards an object of the same type of charge, in an electric field, a force is required
Therefore V = W(fd) / Q
Define electric potential
The work done per unit positive charge on a positive test charge when it is moved from infinity to that point
Explain why potential is measured in V
Pd is also = w/Q
Therefore potential is measured in volts
What is potential gradient in an electric field
The change of potential per unit charge of distance in a given direction
Describe the graph of potential relative to the negative plate against distance
Straight line through the origin
Potential gradient in a uniform electric field is…
Constant
Such that the potential increases in the opposite direction to the field
Equal to V/d
The electric field strength is equal to…
The negative of the potential gradient
State the equation for electric potential
V = 1/4πe x Q/r
When is the value of potential positive?
When in the field of a postive source charge
When is the value of potential negative?
When the source charge is negative and the force is attractive
Define electric potential difference
the energy needed to move a unit charge between two points
(Think of a voltmeter- it measures between two points)
Electric field strength is equal to…
The potential gradient
Electric potential is a property…
of the field created by the source charge
The potential energy of a system depends on…
both the source charge and the test charge
If the test charge is negative and the source charge positive, will the potential energy of the system be positive of negative?
Negative
