Ohms’ Law and Electrical Energy

I wrote an entry as titled above in my thesis draft. But my supervisor asked me to remove it due to irrelevance. I guess she might be correct. So, as to not waste on my writing effort, I’ll just post them here for the benefit of others.


Ohm’s law explains very easily the relationship between the parameters that matters in electricity (V=IR which then relates to power, P=IV). However, the concept of electrical energy is often misunderstood. The following two paragraphs discuss the term current and its connection to electrical energy and power in classical physics without delving into quantum field theory (Appendix F).

The flow of charge creates electrical current. Electric current, measured in Amperes, is defined as the rate of one Coulomb of charge flowing per second. Thus, current is not the flow of electrical energy. In solid metals such as copper, current is the flow of electrons (charge) in a closed loop. In this closed loop, electrons are not consumed by the load. Instead electrons move very slowly from the source through the load and back to the source. However, the flow of electrons creates electrical and magnetic field, which is known as EM fields or waves. This EM wave is also known as the electrical energy.

The flow of electrical energy is known as electrical power and is measured in Joules per second or Watts. Electrical energy is consumed by the load and makes electrical systems work. The EM wave travels almost at the speed of light in the atmosphere. Although electrons flow very slowly in solid metals, the resulting EM waves created from the flow are not confined to any individual electrons. As such, electrical energy travels very fast although the electrical charge may flow very slowly.


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