Parallel Plate Capacitor and Dielectrics

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I have a lab to do tomorrow with this topic. Just wondering if anyone can tell me a brief summary of what this is about and what I should be looking to accomplish/learn

 

[UrbanXrisis]

1. A negatively charged rod is placed next to the neutral electroscope. This causes the electrons to gather away from the rod. There is a gather of negative charge and the leaves repel each other. Next, then the rod touches the electroscope, the electrons will be transferred to the electroscope. There is now a greater charge and the leaves separate more. When the rod is taken way, the electrons are spread evenly around the electroscope. The charge of the electroscope is negative.
When the negatively charged rod is placed next to the electroscope, the electrons will gather away from the rod and there is a concentration of negative charge so the leaves repel each other. When the positively charged rod is placed next to the electroscope, the negative charges will gather towards the rod and cause a less negative charge on the leaves, causing a reduced separation.

2. A positively charged rod is placed next to the neutral electroscope. This causes the electrons to gather closer to the rod. There is a separation of charge and the leaves repel each other. Next, then the rod touches the electroscope, the electrons will be transferred to the rod. There is now a greater positive charge and the leaves separate more. When the rod is taken way, the electrons are spread evenly around the electroscope. The charge of the electroscope is positive.
When the negatively charged rod is placed next to the electroscope, the electrons will gather away from the rod and cause a less positive charge, which reduces the separation. When the positively charged rod is placed next to the electroscope, the negative charges will gather towards the rod and cause a more concentrated positive charge causing more separation.

3. A negatively charged rod is placed next to the neutral electroscope. This causes the electrons to gather away from the rod. There is a gather of charge and the leaves repel each other. Next, the finger grounds electrons making less electrons in the electroscope. When everything is removed, the electrons will spread evenly around the electroscope.
When the negatively charged rod is placed next to the electroscope, the electrons will gather away from the rod and cause a less positive charge, which reduces the separation. When the positively charged rod is placed next to the electroscope, the negative charges will gather towards the rod and cause a more concentrated positive charge causing more separation.

4. A positively charged rod is placed next to the neutral electroscope. This causes the electrons to gather near the rod. There is a gather of charge and the leaves repel each other. Next, the finger transfers electrons into the electroscope. When everything is removed, the electrons will spread evenly around the electroscope.
When the negatively charged rod is placed next to the electroscope, the electrons will gather away from the rod and there is a concentration of negative charge so the leaves repel each other. When the positively charged rod is placed next to the electroscope, the negative charges will gather towards the rod and cause a less negative charge on the leaves, causing a reduced separation.

ps-try to post this in the homework section

 

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thanks a lot!