Three charges 2q,-q,-q are located at the vertices of an equilateral triangle. At the centre of the triangle:
Correct answer: B. The electric field is non-zero, but the potential is zero
- A. The electric field is zero, but the potential is non-zero
- B. The electric field is non-zero, but the potential is zero
- C. Both the electric field and potential are zero
- D. Both the electric field and potential are non-zero
Explanation
The potential is a scalar and sums to V = k(2q)/r + k(-q)/r + k(-q)/r = 0. The electric field is a vector; the fields from the two -q charges sum to a vector that points away from the 2q charge, so the net field is non-zero.
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Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.
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