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Day 15: Electric Potential due to Point Charges. The Electric Potential of a Point Charge Work done to bring two point charges together The Electric Potential at an arbitrary point, due to two point charges. The Electric Potential of a Point Charge. The Electric Field at a distance r away
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Day 15: Electric Potential due to Point Charges • The Electric Potential of a Point Charge • Work done to bring two point charges together • The Electric Potential at an arbitrary point, due to two point charges
The Electric Potential of a Point Charge • The Electric Field at a distance r away from a point charge Q is: • The Electric Potential difference between points a and b can be derived as:
The Electric Potential of a Point Charge • It is common to choose the potential at ∞ as zero. For rb = ∞, Vb = 0 and:
Work Done to Bring Two Point Charges Together • The work done to bring two point charges together is equivalent to the change in the potential energy of the two charges +Q q rb ra = ∞ • If ra = ∞, then:
Electric Potential at an Arbitrary Point due to Two Point Charges • To find the electric potential due to two point charges, simply take the sum of the potentials, at that point, due to each charge. r1 P +Q1r2 Q2 • Note – these arenot vector quantities !