Electric potential

what is the electric potential of a point charge defined as?

the work done per unit charge in taking a small positive test charge from infinity to a defined point.

what is electric potential at infinity?

zero

what does electric potential depend on?

the magnitude of charge and the distance from the charge.

how does electric potential change as you move closer to a positive charge vs a negative charge?

positive- increases

negative- decreases

what is the formula for electric potential due to a point charge?

V= Q/4πε₀r

Q= magnitude of charge producing the potential, r=distance from the centre of the point charge

what is the potential inside a charged sphere?

It is constant

how do you find the combined potential from multiple charges?

add the individual potentials together

what is the graph of potential against distance for a positive charge?

V is proportional to 1/r

whta is the potential gradient of an electric field?

the rate of change of electric potential with respect to displacement in the direction of the field.

what is the graph of potential and distance?

- gradient= electric field strength at that point, the negative sign indicates that the direction of the field strength opposes the direction of increasing potential.

all values of potential are positive for a positive charge, all values are negative for a negative charge.

what is the graph of electric field strength and distance?

all values of field strength are negative for a negative charge, all values of field strength are positive for a positive charge.

the area under this graph is is the change in electric potential.

what is work done equal to?

the change in electric potential energy, work is done when a positive charge in an electric field moves against the field lines or when a negative charge moves with the field lines

what is the equation for change in electric potential energy?

Qq/4πε₀ (1/r₂ - 1/r₁)

Q= charge that is producing electric field, q= charge that is moving in electric field

r₁= initial distance of q from centre of Q, r₂= final distance of q from centre of Q

what is the difference between electric potential and electric potential energy?

electric potential is the work done per unit charge to bring a small positive test charge from infinity to a point in the field, measured in volts, electric potential energy is the energy a charge has because of its position in an electric field. Ep=qV

what are equipotential lines and surafaces?

lines and surfaces that join together points with the same electric potential.

what does the spacing between equipotential lines indicate?

the strength of the electric field, they represent the potential gradient.