what is electricity? top most Relevant Definition and exam useful important facts,

what is Electricity?

• Electricity is a physical phenomenon of the presence and flow of charges. The transfer of charges is the reason for the generation of electricity.

• Electricity is at the core of many modern technologies being used today. Electrical power is necessary to activate devices.

• In the present context, in all our work, be it industrial, domestic or any other type of work, the contribution of electricity remains paramount.

Types of Electricity-

Electricity is mainly classified into two parts

1. Static electricity
2. Dynamic electricity

Static Electricity-

Static electricity refers to the resting state of electrons, which is created by some rubbing or friction between two objects.

• The credit for the production of static electricity by static charges goes to scientist Thales. Whereas the positive or negative properties of charges were described by Benjamin Franklin.

• The only drawback of static electricity is that the electric current generated by it cannot be transferred. This is the reason that led to the birth of dynamic electricity.

what is electricity fact?

If a glass rod is rubbed with a silk cloth, then due to the electrostatic effect the glass rod becomes positively charged and the silk cloth becomes negatively charged.

If you rub an amber rod against leather, the amber rod becomes negatively charged and the leather becomes positively charged. This process is the result of static electricity.

Negatively charged particles-

excess of electrons or availability of electrons.

Positively charged particles-

lack of electrons or absence of electrons. In fact, positive charge only indicates decrease in charge.

Dynamic Electricity-

• Electricity generated by moving charges is called dynamic electricity. Dynamic electricity is of thermoelectric, photoelectric, pressure electric type etc.

• The advantage of dynamic electricity is that it can be transferred from one place to another, making its use very easy.

• Accordingly, dynamic electricity is more useful than static electricity.

• The nature of electricity depends on the internal structure of the atoms of the substance.

Free Electron Concept-

• The flow of electricity in any solid substance is due to the free electrons present in it.

• These free electrons move in elliptical motion in the conduction band or the outermost orbit of the atom.

• Due to the spin of electrons, the electrons which are bound by less intermolecular forces, get forced by any external thermal, optical or magnetic effect and leave their orbit and go into the conduction band and as a result electric current flows.

Important Terms:-

.what is Electric Field?

• The region around a charge in which other charges experience electric current is called an electric field. -Other names- Dielectric constant field or electrostatic field.

• The path of a charged particle in an electric field is parabolic.

• Electric field is a vector field, and its unit is volt.

Electric Field Lines-

• Lines that indicate the presence of an electric field.

• These lines of force are imaginary.

• Lines of force never cross each other.

• Electric lines of force are always tense.

• In electrostatics the electric field lines are never in a closed loop.

• Electric force lines always move from positive charge to negative charge.

Stage First-

The force of attraction exists between the two dissimilar charges. Hence, they have the property of attraction.

Stage Second-

Two equal and similar charges always repel each other.

Due to an isolated positive charge these lines of force are radially outward and due to an isolated negative charge they are inward.

what is Electric Flux?

• The total number of lines of force starting from a charge is called electric flux.

• Let’s denote it by $(phi).

• The unit of electric flux is volt meter.

• Its other unit is newton square meter per coulomb.

• Electric flux is a scalar quantity.

• Its dimensional formula is (M² L3T3 A¹).

Electric Field Intensity

• The electric force acting on a unit charge is called the electric field intensity.

• It is represented symbolically by ‘E’.

• This is a vector quantity.

• Unit: In SI it is newton per coulomb or volt per meter.

Electric Flux Density-

The amount of electric flux per square meter passing through the lines of force in a direction perpendicular to the electric field is called electric flux density.

It is represented symbolically by ‘D’.

D= Q charge/ A area

Unit- coulomb per square meter

what is  electric potential difference?

• Electric potential is a physical quantity that determines the direction of charge flow between two charged objects.

• The work done against the electric force in bringing a unit positive charge to a point in an electric field is called electric potential.

• Electric potential (V) = w/q unit – joule per coulomb or volt

• Electric current always flows from higher potential to lower potential.

• This is a scalar quantity.

• Its dimensional formula is (ML2T-3A).

Potential Gradient-

• The rate of change of potential with respect to distance in an electric field is called potential gradient.

potential gradient- dv/ dr

• Unit- volt per meter or newton per coulomb.

• This is a vector quantity.

• Potential gradient is always from lower potential to higher potential.

Electric field intensity = – (potential gradient or -ve)

E =-(dv/dr)

• Here the “-ve” sign indicates that as the potential increases inwards then the electric field will be opposite to it, directly upwards.

• If the potential difference between two metal plates is (v) and the distance between them is (d), then the electric field intensity between the plates is (E)

E= v/d =means volts per meter

• For any system, when the value of electric potential is zero, the value of electric field intensity will definitely be zero. However, it is not necessary that the value of electric potential is zero when the electric field intensity is zero.

Equipotential Surface-

As the name suggests, the surface on which the potential value at every point remains the same is called an equipotential surface.

For an equipotential surface the potential gradient is zero. Due to which the value of electric field intensity is also zero.

Electric lines of force always cross an equipotential surface in the perpendicular direction.

Potential Difference-

Potential difference is the voltage difference between two points in a circuit that causes current to flow.

The flow of current in a circuit cannot be conceptualised without voltage potential difference.

The unit is volt or joule per coulomb.

This is a scalar quantity.

Electromotive Force-

It is the force or energy that flows through a circuit gives momentum to the electron.

EMF = energy or work done/charge

This is a scalar quantity.

Unit- volt or joule per coulomb.

It should be known that the value of electromotive force is always more than the potential difference.

what is Electricity Current?

• The rate of flow of electric charge in a conductor is called electric current.

• The flow of electrons is also called electric current.

• The direction of flow of electric current is opposite to the direction of flow of electrons.

• The speed of electric current is 3×108 meters per second.

• Electric current is represented by “.”

• The unit of electric current is ampere or coulomb per second.

• Electric current always flows in a closed circuit.

• Electric current always chooses the path of low resistance. On this basis, it flows with its full current value in a short circuit.

• Electric current does not obey the vector addition rule, hence it is a scalar quantity.

Ampere-

• Ampere is the basic unit of electric current in SI. Its name

• Named after André Marie Ampère, the scientist who discovered electromagnetism.

• The constant value of electric current, which when passed through the solution of silver nitrate (AgNO3) collects 0.01118 grams of silver per second, will be one ampere value.

• It is symbolically expressed by ‘A’.

Types of Electric Current-

(A) Direct Current

(B) Alternating Current

Direct current-

Direct Current (DC) is a type of electric current where the flow of electric charge is one direction, meaning that electrons move in a constant direction. It is the opposite of Alternating Current (AC), where the flow of current reverses direction periodically.

• That current whose value and direction always remain constant.

• DC current is obtained from cells, batteries and D.C. generators.

• The frequency of direct current is zero.

• Uses- electroplating, battery charging.

Alternating current

Alternating Current (AC) is a type of electric current in which the flow of electric charge periodically reverses direction. Unlike Direct Current (DC), where the current flows only in one direction, AC switches direction back and forth at regular intervals.

• The current whose value and direction changes with time.

• Alternating current is obtained from the alternator.

• Uses- Domestic, Industrial area etc.

Effects of electric current-

When electric current flows in a circuit, it displays various effects.

The main effects of electric current are as follows-

what is electricity effect?

Chemical Effect-

When electric current is passed through an electrolyte (copper sulphate solution) both the electrons and the positive ions of copper carry out the flow of electric current.

Uses- In electroplating, battery charging, metal refineries etc.

Heating Effect-

As electric current flows through a conductor, resistance opposes its flow, thereby producing heat. The conversion of electrical energy into heat energy is called Joule heating.

Uses- in electric iron, heater, electric lamp etc.

Magnetic Effect-

During the flow of electric current in a conductor a magnetic field is produced perpendicular to the direction of current flow.

Uses- in electric bells, motors and generators etc.

Gas Ionization Effect-

When the electron passes through some part of the glass tube, ionization starts occurring and emission of light rays begins.

Uses- in fluorescent tubes, mercury vapour lamps, neon lamps etc.

Special Rays Effect

X-rays and laser rays are produced by electric current.

Uses- In medical field like X-ray etc.

Shock Effect-

If electric current in excess of the prescribed amount flows through the human body it can cause a dangerous shock and may even lead to death.

Mild electrical shocks controlled at a specific value are used in the treatment of mentally ill people.

exam useful important facts

• The unit of electric die pole movement is coulomb meter.

• Electric field can deflect alpha particle.

• In an equipotential surface the electric field is always perpendicular (90°) to the surface.

• The weight of a molecule is equal to the sum of neutrons and protons.

• Standard temperature and pressure is 273K or 1 atmosphere (atm) pressure.

• The force between parallel current carrying wires is defined by Ampere’s law.

• If current flows in the same direction in two parallel conductors, they attract each other. On the contrary, if current flows in opposite directions, they will repel each other.

calculation

Many people wonder, what is electricity? To answer this, we must explore both the science and math behind it. What is electricity if not the flow of electric charge, often carried by electrons through a conductor like copper wire? When we ask, what is electricity, we’re really asking how energy moves in our daily lives. For example, suppose you have a 60-watt light bulb and you leave it on for 5 hours. To calculate the energy used, you multiply power by time: 60 watts × 5 hours = 300 watt-hours (Wh).

Understanding this helps clarify what is electricity in practical terms. Some students ask, what is electricity made of? The answer lies in atoms and charged particles. When people work on circuits, they often ask, what is electricity doing at each point? Scientists continue to refine their understanding of what is electricity, using both theory and experimentation. In classrooms, teachers ask students, what is electricity, to spark curiosity. Finally, for anyone learning physics, it’s essential to grasp what is electricity and how it powers the world.

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