A balloon and a section of a wall both have neutral charges, as shown below.




A student rubs his hair on the balloon, giving it a negative charge. How will the charges be arranged in the wall when it is placed near the negatively changed balloon?

The negative charge on the balloon will induce a positive charge on the section of the wall nearest to it. This is because opposite charges attract each other. Therefore, the charges on the wall will be arranged with a positive charge closest to the negatively charged balloon and a corresponding negative charge farther away from the balloon.