A scientist wipes a rubber rod with a wool cloth which leads to a negative charge on the rod. After this, the scientist touches the rod to a neutral metal sphere. This will transfer the negative charges from the rod to the sphere:

Question

Which statement explains what will happen to the negative charge, and why?

It will only spread to the air around the sphere, because negative charges need to occupy a big area.
It will only spread to the air around the sphere, because negative charges need to occupy a big area.

It will spread uniformly over the surface of the sphere, because of the conducting nature of the sphere and similar charges push away from each other.
It will spread uniformly over the surface of the sphere, because of the conducting nature of the sphere and similar charges push away from each other.

It will remain only on one spot of the sphere, because the low conductivity of the metal prevents the charges from spreading out.
It will remain only on one spot of the sphere, because the low conductivity of the metal prevents the charges from spreading out.

It will slowly move to the bottom of the sphere, because the charges are heavy and will sink to the bottom.

Answer 1

The correct statement is:

It will spread uniformly over the surface of the sphere, because of the conducting nature of the sphere and similar charges push away from each other.

When a negatively charged rubber rod touches a neutral metal sphere, the excess negative charges (electrons) from the rod will transfer to the sphere. Because the metal sphere is a conductor, these negative charges will redistribute themselves uniformly over the surface of the sphere. This distribution occurs because like charges repel each other, causing the charges to spread out as much as possible across the surface of the conductor. This is a characteristic behavior of conductors, which allows free movement of electrons.