Two point charges +2q and -q are separated by distance d. The point where the electric field is zero lies on the line joining them at a distance from +2q of:
Correct answer: C. d/(1 + √2)
- A. d/3
- B. d/√2
- C. d/(1 + √2)
- D. 2d/3
Explanation
Let the point be at distance x from +2q. The fields due to +2q and -q cancel: k(2q)/x² = kq/(d - x)². Solving, x² = 2(d - x)² gives x = d/(1 + √2). This is a hard-level question due to the algebraic complexity.
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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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