Electric potential near a point charge
What is the electric potential 0.3 m from a +2 nC point charge? (k = 9 × 10⁹ N·m²/C²)
Answer B: explanation for every choice
A
This multiplies kq by r instead of dividing.
B
Correct. V = kq/r = (9 × 10⁹)(2 × 10⁻⁹)/0.3 = 18/0.3 = 60 V.
C
200 V/m is the electric field, kq/r², not the potential.
D
This uses r = 0.03 m.
TakeawayPotential: V = kq/r. Field: E = kq/r².
Equation usedElectric potential and potential energy
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