Electric Field - Physical Significance of Electric Field

Two point charges q_A = 3 μC and q_B = −3 μC are located 20 cm apart in vacuum.

1. What is the electric field at the midpoint O of the line AB joining the two charges?
2. If a negative test charge of magnitude 1.5 × 10⁻⁹ C is placed at this point, what is the force experienced by the test charge?

Electrostatic force is the force exerted by ______.

If a positive charge is shifted from a low-potential region to a high-potential region, the electric potential energy ______.

An oil drop of 12 excess electrons is held stationary under a constant electric field of 2.55 × 10⁴ N C⁻¹ (Millikan’s oil drop experiment). The density of the oil is 1.26 g cm⁻³. Estimate the radius of the drop. (g = 9.81 m s⁻²; e = 1.60 × 10⁻¹⁹ C).

If 10⁹ electrons move out of a body to another body every second, how much time is approximately required to get a total charge of 1C on the other body?

Two equal positive charges are kept at points A and B. The electric potential at the points between A and B (excluding these points) is situated while moving from A to B. The potential