A Van de Graaff generator uses a moving belt to remove electrons from the metal sphere at the top.

If a stack of aluminum pie pans are placed on top of this device, they will ‘fly' off, one right after another. Which statement best describes this phenomenon?

• The pans become negatively charged and are thus repelled from each other
• The pans become positively charged and are thus repelled from each other
• Some pans become positively charged and others become negatively charged
• The north poles of the pans are repelled by the north pole of the Van de Graaff generator
• Other__________________________