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Home Minds On Static Electricity Mission SE5 Charging by Induction - Pop Can Induction Help Help 7

Mission SE5 Charging by Induction - Pop Can Induction

The Question

Two neutral conducting pop cans are touching each other. A negatively charged balloon is brought near Can X. Once brought near, one might notice that can X has an excess of ____ charge and can Y has an excess of ____ charge.

Physics Rules

Charging by Induction:
Charging by induction is a charging process that involves charging an object without touching the object to a charged object. The charged object is brought near to the object to be charged (a neutral object). The charged object's presence induces a movement of electrons within the neutral object, causing it to become polarized. Then the neutral object is touched to a ground, causing a transfer of electrons between ground the neutral object. The ground is pulled away, the charged object is pulled away and the neutral object has been charged. When the process is complete, both objects are charged with the opposite type of charge.

Think About It

Opposites attract. Likes repel. And only electrons can move. That's the key to understanding charging by induction. The role of the charged balloon in the induction charging process is to induce a movement of electrons within the nearby can X. A negatively charged balloon will repel electrons and a positively charged balloon will attract electrons. Since the pop cans consist of conducting materials and are touching each other, the movement of electrons does not end or start at the edge of can X. Electrons can move from can X to can Y or vice versa. This movement of electrons causes the two cans to be polarized. Knowing which can has excess positive charge and which can has excess negative charge is a simple matter of applying the slogan opposites attract and likes repel.

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