A teacher places a metal can on top of an insulating foam cup and touches the side of the foam cup with a negatively charged rod.

Question

What will happen to the negatively charged electrons when the rod touches the foam cup?

The electrons will transfer to the foam cup and will remain in a concentrated, positively charged area on the cup where the rod was placed.
The electrons will transfer to the foam cup and will remain in a concentrated, negatively charged area on the cup where the rod was placed.
The electrons will transfer from the foam cup to the metal can, causing both cup and can to have a positive charge.
The electrons will transfer from the foam cup to the metal can, causing both cup and can to have a negative charge.

Answer 1

When the negatively charged rod touches the side of the foam cup, the excess electrons from the rod will transfer to the foam cup. This results in the foam cup becoming negatively charged due to the added electrons.

Thus, the correct statement is:

The electrons will transfer to the foam cup and will remain in a concentrated, negatively charged area on the cup where the rod was placed.