Sunday, January 15, 2012

Mystery of "V x I" - 2 or What Electric Energy is?

This is a continuation of the previous post titled Mystery of "Power = V x I" with some additional information and thinking.

Mystery of "Power = V x I" was posted before as

"
V (Joule/Coulomb) x I (Coulomb/second) = Power (Joule/sec = Energy/sec). So after multiplication of V by I, Coulomb (unit of electric charge) disappears like a magic and only Energy and time remain. This explains well that Current is not consumed in a load such as a resistor and a light bulb - Kirchhoff's Current law but Energy is consumed, changed to some other form of Energy - conservation of Energy.

"

Question - Why Charges disappear after I x V (= Power) and Energy

remains ?

Assumption 1 - Charge only carries Energy.

One example


Electronics Club

Electricity and the Electron

Next Page: Series and Parallel Connections
Also see: Circuit Symbols and Circuit Diagrams

What is electricity?

Lamp switching on and off Electricity is the flow of charge around a circuit carrying energy from the battery (or power supply) to components such as lamps and motors.

Electricity can flow only if there is a complete circuit from the battery through wires to components and back to the battery again.

The diagram shows a simple circuit of a battery, wires, a switch and a lamp. The switch works by breaking the circuit.

With the switch open the circuit is broken - so electricity cannot flow and the lamp is off.

With the switch closed the circuit is complete - allowing electricity to flow and the lamp is on. The electricity is carrying energy from the battery to the lamp.

We can see, hear or feel the effects of electricity flowing such as a lamp lighting, a bell ringing, or a motor turning - but we cannot see the electricity itself, so which way is it flowing?

-----

This (Electricity is the flow of charge around a circuit carrying energy) explains "Current is not consumed in a load such as a resistor and a light bulb - Kirchhoff's Current law" but does not explain how current (charges) carry energy. No equation shows the relation between electricity and energy. Charges seem to be carriers of energy. No definitions on what electricity is, what electric energy is.



Assumption 2 - Charge creates Energy by moving (mechanical Energy).

Current is a flow (motion) of charges.

E_{kinetic} = \tfrac 1 2 m v^2 \,\!

To move charges potential energy from some energy source like a battery (chemical energy) , capacitor (stored energy (1/2) C V2 ) and inductor (stored energy (1/2) L I2 ) is required and used.

An electron has a charge (−1.602176565(35)×10−19 C) as well as a mass (9.10938291(40)×10−31 kg). It flows so have velocity. How fast? changing direction?

1) DC current in a conductor or somewhere in a conductive material in a circuit is not very fast and may not necessarily move straight (not 1D but 3D)

2) AC current moves back and forth in a circuit and changes direction slowly or fast with different frequencies.

3) More generally electron move dynamically according to the electromagnetic field conditions.

4) Electron spins which requires mechanical energy.

5) Electron is not a rigid body. E_{kinetic}       = \tfrac 1 2 m v^2 \,\! cannot be applied to electron.

6) Electron motion or behavior or status in terms of energy is believed be more precisely described by quantum properties.


sptt

No comments:

Post a Comment