Exploring the Effects of Electrostatic Induction on Neutral Objects

In summary, induction works by bringing a charged object near a conductor, and the leaves become negatively charged and repel. This happens because the charges on the rod and the conductor become repelled and leave exposed ions.
  • #1
punjabi_monster
60
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This is my understanding of induction:
If a negatively charged rod is brought near (but not touching) a neutral electroscope, the positive charges will move towards the rod, and the leaves will become negatively charged and repel. If grounded, electrons will exit the electroscope, and the electroscope will have a positive charge.

What i do not understand is when the rod is brought near the neutral electroscope, why the leaves get negatively charged?
 
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  • #2
That's actually a kind of complicated question! Ideally, it's supposed to work like this. When you bring a charged object (like the rod) near a conductor (like the electroscope leaves) the electric field of the rod interacts with the charges that make up the conductor.

Now the conductor is a NEUTRAL object but being a conductor it has some very special properties. The ions in the lattice tend to be bound in place in a sort of lattice structure. They are big and heavy compared with the electrons many of which enjoy walking about like social butterflies but not wanting to be associated with any particular ion. They are mobile and free to move about as they please and everything is harmonious as long as everything remains (net) neutral.

However, when the charged rod gets closer those conducting electrons become a bit skittish and are repelled by the oncoming electrons (like charges repel) so they tend to move away to the furthest reaches of their conducting home. In their wake, they leave somewhat exposed ions that want to move toward the rod's electrons (opposite charges attract). Even though the conductor remains neutral, the charges (electrons and ions) are no longer evenly distributed so the electrons in the rod and the ions in the conductor tug away fondly at each other and you observe the attraction.

In practice, matters become just a little more complicated particularly if the attraction is a little too strong. Some of the electrons on the rod can actually make the jump from the rod to the conductor across the gap between them. This would leave a small residual charge on the conducting leaf. They would eventually go away after you remove the rod but that takes time. You speed up the process of removing the excess charge by grounding it.
 
  • #3
ok thanks a lot. :approve: :smile:
 

1. What is electrostatics?

Electrostatics is the study of electric charges at rest and the forces they exert on each other. It deals with the behavior of stationary electric charges and the electric fields they create.

2. How are electrostatic forces different from electromagnetic forces?

Electrostatic forces are caused by stationary electric charges, while electromagnetic forces are caused by moving electric charges and changing magnetic fields. Electrostatic forces are much stronger than electromagnetic forces at short distances.

3. What is induction in electrostatics?

Induction is the process by which an electric field can influence the distribution of charges in a conductor, causing them to redistribute and create an induced electric field. This can occur without any physical contact between the two objects.

4. What is the difference between conductors and insulators in electrostatics?

Conductors are materials that allow electric charges to move freely, while insulators are materials that resist the flow of electric charges. In electrostatics, conductors are important for creating and manipulating electric fields, while insulators are useful for preventing unwanted electric charges.

5. How is electrostatic induction used in everyday life?

Electrostatic induction is used in many devices and technologies, such as generators, capacitors, and electrostatic precipitators. It is also used in everyday items like photocopiers, air purifiers, and touch screens in smartphones and tablets.

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