Question

what is electrical energy? Derive its expression and define its unit?​

Answer 1

Answer:

Electrical energy is a form of energy resulting from the flow of electric charge . energy is the ability to do work or apply force to move an object . the movement it of charged particle through a wire or other medium is called current .

SI unit of electrical energy is watt.

hope it's help you....

Answer 2

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what is electrical energy? Derive its expression and define its unit?

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What is an Electrical Energy?

• Electrical energy is the energy derived from electric potential energy or kinetic energy of the charged particles. In general, it is referred to as the energy that has been converted from electric potential energy. We can define electrical energy as the energy generated by the movement of electrons from one point to another. The movement of charged particles along/through a medium (say wire) constitute current or electricity.

Electrical Energy Formula

Electric Power Lines :-

• A cell has two terminals – a negative and a positive terminal. The negative terminal has the excess of electrons whereas the positive terminal has a deficiency of electrons. Let us take the positive terminal as A and the electrical potential at A is given by V(A). Similarly, the negative terminal is B and the electrical potential at B is given by V(B). Electric current flows from A to B, and thus V(A) > V (B).

The potential difference between A and B is given by :-

• V = V(A) – V(B) > 0

• Mathematically, electric current is defined as the rate of flow of charge through the cross-section of a conductor.

• Thus, it is given by I = ∆Q/ ∆t where I is the electric current and ∆Q is the quantity of electric charge flowing through a point in time ∆t.

• The potential energy of charge Q at A is Q V(A) and at B, it is Q V(B). So the change in the potential energy is given by

• ∆Upot = Final potential energy – Initial potential energy

• = ∆Q [(V (B) – V (A)] = –∆Q V

• = –I V∆t (Since I = ∆Q/ ∆t)

• If we take the kinetic energy of the system into account, it would also change if the charges inside the conductor moved without collision. This is to keep the total energy of the system unchanged. Thus, by conservation of total energy, we have:

• ∆K = –∆Upot

• Or ∆K = I V∆t > 0

• Thus, in the electric field, if the charges move freely across the conductor, there would be an increase in the kinetic energy as they move.

• When the charges collide, the energy gained by them is shared between the atoms. Consequently, the vibration of the atoms increases resulting in the heating up of the conductor. Thus, some amount of energy is dissipated in the form of heat in an actual conductor.

Units of Electrical Energy

• The basic unit of electrical energy is the joule or watt-second. An electrical energy is said to be one joule when one ampere of current flows through the circuit for a second when the potential difference of one volt is applied across it. The commercial unit of electrical energy is the kilowatt-hour (kWh) which is also knwon as the Board of trade unit (B.O.T).

• 1 kwh = 1000 × 60 × 60 watt – second

• 1 kwh = 36 × 105 Ws or Joules

Generally, one kwh is called one unit.

What are some examples of electrical energy?

A few examples of electrical energy are:

• In a car battery, a chemical reaction results in the formation of an electron which possesses the energy to move in an electric current. These moving charges provide electrical energy to the circuits in the car.

• Lightning, during a thunderstorm, is an example of electrical energy – what we see as lightning is nothing but electricity discharging in the atmosphere.

• Electric eels generate electrical energy and use it against predators for defence.

Electrical Energy Into Mechanical Energy

• Electrical energy can be converted into other forms of energy like heat energy, light energy, motion etc. The best-known example are:

• Fan: The motor in Fan converts electrical energy into mechanical energy

• Bulb: Here the electrical energy is converted into light energy.