The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

Conductors are substances which allow electricity to pass through them easily. This is due to the presence of electric charges (electrons) within them, which move around freely within the material. Metals, humans, animal bodies, and earth are examples of Conductors.

In the process of **charging by induction**, a neutral conducting object is brought near a charged object with no physical contact between the two. The presence of charged objects near the neutral conductor forces the electrons within the conductor to move.

During the process of **charging by induction**, a charge is shared between two conductors when an uncharged conductor is brought in contact with a charged conductor. This way the uncharged conductor gets charged and both the objects acquire the same type of charge.

**Coulomb’s Law** states that that the mutual electrostatic force existing between two point charges A and B is proportional to their product, which is AB, and inversely proportional to the square of the distance between them (r12).

where,

F = Force

R = Distance in Vacuum

q1 and q2 = Two point charges

K = 9*109Nm2C−2 Nm2C−2

It is proven experimentally when taken one at a time, the force on any charge due to a number of other charges is the vector sum of all the forces on that charge due to the other charges. With the presence of other charges, individual forces are unaffected, which is termed as the principle of superposition.

Consider q1, q2 and q3 as three charges of a system. Here, if the force on q1 due to q2 is denoted by F12.

Where, F = electric force

K= 1/(4πε) = coulomb’s constant

q= charge

r= distance of separation

**Charges are Additive in Nature** – Charges can be added directly, and scalar in quantity, as they have only magnitude and no direction.

Algebraic sum for a system = q1 + q2 + q3 + q4 + … + qn

Where, q= charge

**Charge is Conserved Quantity** – Charges can neither be created nor be destroyed. They can only be transferred from one body to another through the means of conduction and induction.

**Quantization of Charge** – Charge is a quantized quantity and is expressed as integral multiples of the basic unit of charge (e – charge on one electron).

q = number of electrons/ protons * charge on one electron = ne

Here, n can be a positive or a negative integer.

An **Electric Field** is the physical field that surrounds each **electric charge** and exerts a force on all other charges in the field, either attracting or repelling them. Electric fields originate from electric charges or from time-varying magnetic fields.

- The electric force per unit charge is defined as
**Electric Field**. - It is radially outward from a positive charge and radially inward to a negative charge.
**Electric field**is a vector sum.

Where

E = **Electric Field**

Q = Charge of Magnitude

R = Point of Distance

K = Constant value of 8.99 x 109 N m2/C2

A pair of equal and opposite point charges such as q and -q, separated by distance 2a is known as an **Electric Dipole**. The line connecting the two charges defines a direction in space. By convention, the direction from –q to q is said to be the direction of the dipole. The midpoint of –q and q is called the center of the dipole. The total charge of the **electric dipole** is obviously zero.

**Gauss’s Law** or Gauss’s Flux Theorem is a law relating the distribution of **electric charge** to the resulting **electric field**. The surface under consideration may be a closed one enclosing a volume, such as a spherical surface.

With the above discussion, we have learned a few basic concepts of **Electric charges and fields**. We have learned that an **electric charge** could be positive or negative like charges repel each other, and unlike charges attract each other. We have also learned about the process of charging through induction, **Gauss’s Law**, and **Coulomb’s Law**. But there is more in this topic that is left behind; which you can find on MSVgo and explore the world of electricity.

- Electrostatic Potential and Capacitance
- Current Electricity
- Moving Charges and Magnetism
- Magnetism and Matter
- Electromagnetic Induction
- Alternating Current
- Electromagnetic Waves
- Ray Optics and Optical Instruments
- Wave Optics
- Dual Nature of Radiation and Matter
- Atoms
- Nuclei
- Semiconductor Electronics: Materials, Devices and Simple Circuits