Explain about electrostatic induction?
The word induction itself means influence without physical contact. Thus, actually electrostatic induction refers to the charging process without physical contact between the conductors.
If a charged conductor is brought near an uncharged conductor (without touching), it has been found that the later develops and equal and opposite charges on it.
Here, the green positively charged rod induces equal and opposite charges on the blue sphere. Negative charge on the near side of the rod and positive charge on the opposite side.
Electrostatic induction is the production of an unbalanced electric charge on an uncharged metallic body as a result of a charged body being brought near it without touching it. If the charged body is positively charged, electrons in the uncharged body will be attracted toward it; if the opposite end of the body is then grounded, electrons will flow onto it to replace those drawn to the other end, the body thus acquiring a negative charge after the ground connection is broken
The ancient Greeks found that if amber was rubbed with fur it would attract small objects like hair. If the amber is rubbed long enough a small spark could be generated
This process of rubbing, using friction to generate electric charges is not well understood, but is fairly common place. Walking on carpet with socks can generate charges… Petting your cat…
When an object gets charged by induction, a charge is created by the influence of a charged object but not by contact with a charged object. The word induction means to influence without contact. In the example shown below, the electroscope gets charged without any contact with the charged object brought in from the top.
- The charged object is brought near the neutral electroscope. This causes many electrons to move toward the top to be near the positive charge.
- While the charged object is still near (but not touching) a connection to ground (via your finger) is created to the electroscope. In this case, some electrons from your finger are drawn into the electroscope by the charged object. The electroscope now has an excess of electrons, (but often the leaves go flat because the majority of them are at the top, the bottom is neutral. - not shown in this animation )
- The attachment to ground is removed (you take away your finger). This strands the electrons on the electroscope so it now has negative charge.
- Pull the charged object away, the leaves move apart. It is charged!
There are several advantages to charging something by induction.
- The originally charged object never loses any charge so it need not be recharged. (work does not need to be done creating the charge again)
- The induced charge can be quite strong and subsequent charges will be equally strong
You must have often tried rubbing a plastic ruler to your hair and lifting bits of paper with it. Rubbing the plastic ruler with your hair causes the electrons to move from your hair to your ruler. The ruler is now negetively charged.
When this negetively charged ruler is brought close to the paper, the electrons on one side of the paper are repelled and move away. This side is now positively charged. Here the paper was charged without actually touching the ruler to it. In other words, a charge is induced in the paper. This method of charging is called electrostatic induction
Electrostatic induction is the process in which an uncharged body acquires an opposite charge on the nearer end and a similar charge on the farther end when a charged body is kept near it (there has to be some gap between the charged body ans the uncharged body)
Magnetic Induction is the process in which a piece of magnetic material acquires magnetic properties temporarily due to the presence of a magnet nearby it