A positively charged rubber rod is moved close to a neutral copper ball that is resting on a nonconducting sheet of plastic. a) Sketch the distribution of the charges on the ball. b) With the rod still close to the ball, a metal wire is briefly connected from the ball to the earth and then removed. After the rubber is rod is also removed, sketch the distribution of charges(if any) on the copper ball.
We cannot draw sketches for you. Refer to a website that discusses charge by induction, and which has figures.
Refer to the left-hand part of figure 22.2 of the site below for a sketch of what happens.
http://teacher.pas.rochester.edu/phy122/Lecture_Notes/Chapter22/Chapter2206.gif
a) To understand the distribution of charges on the copper ball when a positively charged rubber rod is moved close to it, you need to consider the principle of electrostatic induction. Here's how you can sketch the distribution of charges on the ball:
1. Start by drawing a neutral copper ball (no charges).
2. Place the positively charged rubber rod close to the ball without touching it.
3. Due to its positive charge, the rubber rod repels the electrons in the copper ball, making the electrons move away from the rod and towards the far side of the ball.
4. As a result, the side of the copper ball closest to the rubber rod will have a negative charge accumulation. This negative charge is due to the excess electrons moving away from the rod and toward the ball.
5. On the other side of the copper ball, farthest from the rubber rod, there will be a positive charge accumulation. This positive charge is a result of the protons being relatively more concentrated on this side of the ball since the electrons have moved away.
Therefore, your sketch should show a distribution of negative charges on the side of the copper ball closest to the rubber rod and a distribution of positive charges on the side farthest from the rod.
b) When a metal wire briefly connects the copper ball to the earth and is then removed while the rubber rod is still close to the ball, the excess charges on the copper ball will be neutralized. Follow these steps to sketch the distribution of charges (if any) on the copper ball once the rod and wire are removed:
1. Start with the sketch of the copper ball from part (a), where the charges are distributed as described.
2. Once the metal wire connects the copper ball to the earth, any excess charges on the ball will flow through the wire and be grounded or neutralized.
3. Remove the metal wire from the sketch.
4. Remove the rubber rod from the sketch.
After removing the rod and the wire, the copper ball will be neutral again, meaning that there will be no excess positive or negative charges. Therefore, your sketch should show a neutral distribution of charges on the copper ball, indicating that the charges have been neutralized after the removal of the rod and wire.
a) Initially, the copper ball is neutral, which means it has an equal number of positive and negative charges. When the positively charged rubber rod is moved close to the copper ball, it polarizes the charges in the ball.
The negative charges in the copper ball are attracted to the positively charged rubber rod, causing a slight redistribution of charges. The side of the copper ball facing the rod will have a slightly greater concentration of positive charges, while the side facing away from the rod will have a slightly greater concentration of negative charges.
b) When the metal wire is briefly connected from the copper ball to the earth, it allows the excess charges to flow away, as the earth is a vast reservoir for charge. This process called grounding neutralizes any excess charge on the ball.
After removing the rubber rod and the metal wire, the copper ball will be left with an equal distribution of positive and negative charges, similar to its initial state of being neutral. Therefore, the distribution of charges on the ball will be even across its surface.