How do the charges compare when two objects are charged through friction?

The objects become oppositely charged and have equal amounts of charge.

The objects become positively charged and have equal amounts of charge.

The objects become negatively charged and have different amounts of charge.

The objects become oppositely charged and have different amounts of charge.

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The objects become oppositely charged and have equal amounts of charge.

Explanation:

There are three methods for charging objects:

- Conduction: a charged object is brought in contact with a neutral object. Electrons are transferred from the charged object to the neutral one, which also becomes charged

- Induction: a charged object is brought close (but not in contact) to a neutral object. The charges inside the neutral object redistribute, such that those of opposite sign to the charge in the charged object migrate on the side closer to the charged object, while the charges of same sign migrate towards the opposite side. If the neutral object is then grounded, the charges on the opposite side flow to the ground, leaving the neutral object charged as well

- Friction: two objects initially neutral are rubbed against each other. Electrons move from one object to the other one: therefore, one object becomes positively charged while the other one becomes negatively charged. Since the charge gained by one object is equal to charge lost by the other object, it follows that the two objects have same magnitude of charge, but with opposite sign.