Consider the following sequence of events:
1. You rub a glass stirring rod with a silk cloth, giving the glass rod a positive charge.
2. Your friend holds an aluminum measuring cup in her bare hand, touching the metal.
3. Your friend puts the aluminum cup down on a rubber mat.
4. You bring the glass rod near the right side of the aluminum cup, but not close enough to touch.
5. While you hold the glass rod near the right side of the aluminum cup, your friend touches the left side of the cup with her
finger, then moves her finger away.
6. You move the glass rod away from the cup.
Which statements about the process are true?
In step 4, protons flow from the aluminum cup onto the rubber mat.
At the beginning of step 3 the cup was neutral.
Since the glass rod does not touch the cup in steps 4 thorough 6, the cup is still neutral after step 6.
After step 6, the aluminum cup has a net negative charge.
In step 5 electrons flowed from the cup to your friend's finger.
At the end of step 2 the cup may have been strongly charged.
At the end of step 4 the aluminum cup is polarized.