Charging by Induction

When we remove our synthetic clothes or sweaters from our bodies, a spark or crackling sound occurs, especially in dry weather. With feminine clothing, such as polyester sarees, this is nearly inescapable. Another form of electric discharge is lightning in the sky during thunderstorms. When we open a car door or grip the iron bar of a bus after slipping out of our seats, we get an electric jolt. The release of electric charges that have accumulated as a result of rubbing insulating surfaces is the source of these feelings. This is related to the creation of static electricity. Static is a term used to describe anything that does not move or change over time. The study of forces, fields, and potentials arising from static charges is referred to as static charge theory.

Charging by induction

In most bodies, electrical neutrality refers to the presence of an equal number of positive and negative charges. The balance of positive and negative charges must be modified to charge a neutral body. The following concepts can be used to change the charge balance of a neutral body:

• Friction

• Conduction

• Induction

Charging by friction

Rubbing one particle against another allows electrons to transfer from one surface to the next, which is how the charging by friction method works. Insulators can be charged using this approach.

Material objects are made up of several sorts of atoms and atom combinations. Because various atoms exist in different items, they have distinct electronic characteristics. One of these qualities is electron affinity. Simply said, electron affinity is a property that describes how concerned a substance is with electrons. If the atoms of a substance have a great affinity for electrons, the material will have a strong affinity for electrons as well.

Charging by conduction

When a charged particle comes into connection with a neutral conductive medium, it charges by conduction. The charged material transmits its charges to the neutral conductor. Conductors can be charged using this technique.

When a charged object makes touch with a neutral object, conduction charging occurs. Assume that a positively charged metal plate collides with a neutral ball. The neutral metal sphere becomes charged when it comes into contact with the charged metal sheet.

Consider the instance of a negatively charged metal sphere placed against a neutral needle electroscope’s top plate. 

Finally, assume an uncharged physics scholar standing on an insulating platform when he or she comes into contact with a negatively charged Van de Graaff generator, which charges the neutral physics scholar.

Charging by induction

Induction charging is a charging method that involves charging a neutral object without contacting another charged object. A neutral or uncharged conductive material grounded on a neutrally charged material is used to hold the charged object. When a charge flows between two objects, the uncharged conductive material develops a charge opposite the charged object’s polarity.

1.Induction charging with a positively charged rod:

Charging by induction using a positively charged rod.

Connect two metal spheres, A and B, by placing them on insulating platforms.

Bring a positively charged rod near one of the spheres, say A, but do not allow it to touch it. 

The free electrons in the spheres are drawn to the rod. There is now an excess of positive ions on the back surface of sphere B. Both types of charges are enclosed in metal spheres, preventing them from escaping. As a result, they prefer to reside on the ground. A negative charge surplus exists on sphere A’s left surface, while a positive charge excess exists on sphere B’s right surface. Not all of the electron particles in the spheres have gathered on A’s left surface. The negative charge repels other electron particles.

The process is known as induction of charge, and it happens very quickly. Until the glass rod is held close to the sphere, as shown, the gathered charges are visible on the surface. The charges are no longer influenced by external pressures and revert to their original neutral state when the rod is removed.

2. Induction charging with a negatively charged rod:

Charging by induction using a negatively charged rod.

Consider the two metal spheres A and B in the diagram, which are touching. Take a negatively charged rod as an example. When a charged rod is held close to the spheres, electrons in the two-sphere system move away due to repulsion between the charged rod’s electrons and the spheres.

As a result, electrons from sphere A are transported to sphere B. Due to electromigration, sphere A becomes positively charged while sphere B becomes negatively charged.

The entire two-sphere system becomes electrically neutral as a result. The spheres are then split as shown (avoiding direct contact with the metal). The charge is dispersed throughout the spheres when the charged rod is removed, as seen in the diagram.

Basic properties of electric charges

Charge Additivity: 

If a system has two point charges, q1 and q2, the total charge of the system can be measured by algebraically adding q1and q2, i.e., Charges can be scalars, like a body’s mass, or they can add up to real numbers. The total charge of a system with n charges (q1, q2, q3,…, qn) equals q1+ q2+ q3+… + qn. Charge has a magnitude but no direction, equivalent to mass. However, there is a distinction to be made between mass and charge. The mass of a body is always positive, whereas the charge can be either positive or negative. Certain indicators must be used when adding charges to a system.

Conservation of Charge: The overall charge of an isolated system will always remain constant, according to the conservation of charge rule. Any system that is not exchanging mass or energy with its surroundings will have the same total charge at any two time intervals. When two objects in an isolated system each have a net charge of zero and one of the bodies transfers one million electrons to the other, the item with the surplus electrons becomes negatively charged, while the object with the less electrons becomes positively charged. The system’s total charge has never changed and will never change.

Conclusion

If a negatively charged object is used to inductive reasoning charge a neutral object, the neutral object will become positive ions. If a positively charged object is used to inductively charge a neutral object, the neutral object will become negatively charged.