Final answer:
When a negatively charged balloon is moved towards a wall, it induces polarization in the wall. The negative charges in the wall are attracted to the balloon, while the positive charges are repelled. This creates a region of positive charge near the surface facing the balloon and a region of negative charge on the opposite side of the wall.
Step-by-step explanation:
When the negatively charged balloon is moved away from the sweater and towards the wall, the positive and negative charges on the wall are affected. As the negatively charged balloon approaches the wall, it induces a separation of charges in the wall through polarization. The negative charges in the wall are attracted to the positively charged balloon, while the positive charges are repelled.
This happens because like charges repel each other, according to Coulomb's law. As a result, the negative charges in the wall move closer to the balloon, creating a region of positive charge in the wall near the surface facing the balloon. Conversely, the positive charges in the wall move away to create a region of negative charge.
Therefore, when the negatively charged balloon is moved towards the wall, the wall becomes polarized, with positive charge near the surface facing the balloon and negative charge on the opposite side.