Final answer:
The electric force on the Moon is negligible because of its weak gravitational pull and lack of atmosphere, leading to minimal interaction for electric charges and dominance of gravitational forces over electrostatic forces.
Step-by-step explanation:
The electric force is negligible on the Moon because of the lack of atmosphere and the low surface gravity, which is about one-sixth that of Earth. The Moon's gravitational pull is too weak to retain a significant atmosphere, meaning that there are fewer atoms and molecules for electric charges to interact with. Moreover, as noted by Newton's law of universal gravitation, the force of gravity decreases with the square of the distance, making the gravitational force at the Moon much less than that on Earth. When electric charges are placed on the Moon, the gravitational forces are still dominant over the electrostatic forces because of the large masses involved.