How Does Charge Transfer Work? Principles, Types, and Applications
What is Charge Transfer?
The charge transfer is illustrated as an electron donor and electron acceptor facility, branded by electronic transitions to an excited state.
There is a fractional transfer of elementary charge from the giver to the recipient in this excited state. In the ultraviolet-visible region, nearly whole charge transfer complexes have strong absorption & exclusive bands.
Separated from charge transfer, connections between giver and recipient, the electrostatic forces also persist. The existing forces are generally much punier than covalent bonds or hydrogen bonds, however valuable for making crystal structures.
Charge Transfer and its Methods
You might have known that when we charge a piece of plastic, a comb, or a pen and place it close to the small pieces of paper, they get attracted to it.
The methods of charge transfer can be explained through this example. As we can observe that the charges get transferred to our hand and eventually to the ground.
There are two methods of charge transfer that can take place between two bodies.
Charging by conduction
Charging by induction
How Do You Transfer a Charge?
Let's discuss the techniques of charging here:
a. Charge transfer by Conduction
The charge transfer by conduction procedure contains the procedure of moving a charged particle to a conductive material.
In this fashion, the charges are traveled from the charged material to the conductor. This process is advantageous for charging conductors.
i. Charge Transfer By Conduction through a Negative Charged Object
Let us consider that a metal sphere possesses a negative charge, as shown in the figure.
When the charged metal sphere interacts with a neutral object, extra electrons from the sphere transfers onto the neutral object and spreads out equally.
Thus, in the result of this process, the object 2 gains negative charge while the metal sphere is quietly charged but has a lesser amount of electrons.
This procedure of charging by contact is called charging by conduction.
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ii. Charge Transfer By Conduction through a Positive Charged Object
We know that a positively charged sphere has additional protons, which means a shortage of electrons. Let us think that there are two objects; one positively charged metal plate and a neutral metal sphere.
When a metal plate possessing a positive charge comes in contact with a metal sphere in a neutral state, the electrons from the neutral sphere get drawn towards the metal plate having a positive charge.
This process continues until the positive charge available on the metal plate becomes reallocated.
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b. Charge Transfer By Induction
Induced-charge departure is a shift in the point of electrons in a neutral object that happens when a charged object is carried close to it. Here, charging by induction is the charging of a neutral object by taking another charged object close to it; without any physical contact of the neutral object.
To charge more than one object by induction, a positively charged object can be utilized to induce a charge in a neutral object. You can also practice two objects at the same time to charge the objects permanently.
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In sphere A, the electrons are pulled by the positive charge on the balloon. Electrons in sphere B are involved with sphere ‘A’ and shifted. Keep the balloon in position and eliminate sphere B from sphere ‘A’, it makes sphere B a positively charged body permanently.
Charge Transfer By Induction through Positive Charged Object
Take two spheres ‘A’ and ‘B’, contact with each other, as shown in the figure.
If we take a positively charged balloon near the sphere ‘A’, the electrons from sphere B will migrate on the way to sphere A because of the attraction between opposite charges.
Accordingly, the sphere ‘A’ acquires negative charges, and sphere ‘B’ acquires positive charges. The spheres are then detached with the help of an insulating cover i.e., a stand or gloves. When the balloon is detached, the charges in sphere A and B will be reorganized, scattering out evenly.
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What is Charge Transfer Complex?
The charge transfer complex is known as the electron recipient or donor complex. The charge complex can be defined as the combination of two or more molecules, or of different parts of a huge molecule where a fraction of electronic charge is transported between the molecular entities.
Charge transfer also occurs sometimes in inorganic metals.
What is Charge Transfer Spectra?
In highly ionic crystals, charge transfer spectra resemble electron transfer between neighboring atoms. It can be divided into a donor or recipient. They are dependent upon whether the metal atom donates or accepts an electron.
The relation between optical and chemical charge transfer progressions is examined to calculate charge transfer spectra.
FAQs on Charge Transfer: Explained with Methods and Examples
1. What is meant by charge transfer in physics?
Charge transfer is the physical process of moving an electric charge, typically electrons, from one atom or object to another. This movement results in one object gaining a net negative charge (by gaining electrons) and the other developing a net positive charge (by losing electrons). It is the fundamental mechanism behind static electricity and is governed by the Law of Conservation of Charge.
2. What are the primary methods of charge transfer covered in the CBSE Class 12 syllabus for 2025-26?
For the CBSE syllabus, there are three primary methods for transferring electric charge:
- Friction (Triboelectric Effect): Charging occurs when two different materials are rubbed together, causing electrons to move from one material to the other based on their electron affinity.
- Conduction: Charge transfer happens through direct physical contact. A charged object touches a neutral or differently charged conductor, and charge flows between them until they reach a common potential.
- Induction: This method charges an object without direct contact. A charged object is brought near a neutral conductor, causing the charges within the conductor to redistribute. The conductor can then be given a net charge by grounding it temporarily.
3. Why does a balloon stick to a wall after being rubbed on your hair?
This is a classic example involving two types of charge transfer. First, when you rub the balloon on your hair, charging by friction occurs, and the balloon gains excess electrons, becoming negatively charged. Then, when you bring the negatively charged balloon near the neutral wall, it repels the electrons in the wall's surface. This charging by induction creates a temporary, localised positive charge on the wall's surface, which attracts the negatively charged balloon.
4. How is charging by induction fundamentally different from charging by conduction?
The fundamental difference lies in physical contact and the resulting charge. In conduction, there is direct contact, and the charge is shared, resulting in both objects having the same type of charge. In induction, there is no physical contact; the charged object merely rearranges the charges in the neutral object. To permanently charge by induction, the neutral object must be grounded, giving it a charge that is opposite to the charging object.
5. When an object is charged, is a new electric charge created?
No, a new charge is never created. This is a common misconception. The process is governed by the Law of Conservation of Charge, which states that charge can neither be created nor destroyed. When an object is charged, electrons are simply transferred from one object to another. The amount of positive charge gained by one object is exactly equal to the amount of negative charge gained by the other, keeping the total charge of the isolated system constant.
6. Is there a single formula for charge transfer?
While there isn't a single formula for the overall process of transfer, the amount of charge that moves is governed by the principle of quantization of charge. This is expressed by the formula q = ne, where 'q' is the total charge transferred, 'n' is an integer (a whole number), and 'e' is the elementary charge of a single electron (approximately 1.602 x 10⁻¹⁹ C). This means charge is always transferred in discrete, whole-number packets, not in fractions of an electron's charge.
7. Why are metals good for charging by conduction, while materials like plastic or wood are not?
The difference is due to the presence of free electrons. Metals are conductors and have a 'sea' of electrons that are not tightly bound to any single atom and can move freely throughout the material. This mobility allows charge to be easily transferred upon contact (conduction) or to be redistributed (induction). In contrast, insulators like plastic and wood have tightly bound electrons that cannot move freely, making it very difficult to transfer charge through them.
