All of us can’t live without electricity, because nowadays electricity and appliances which run on electricity are important parts of our day-to-day life, but have you ever wondered, how this is possible ? Electricity generated 100miles or even 1000 miles away is used by you to run your computers or charge your smartphone. Interesting right?
Well, these unbelievable things are only possible because of current and to be precise in terms of physics “Alternating Current”.
What is an alternating current ?
As you know a current is created when charge flows inside a conductor but what about alternating current ?
Alternating current is something whose magnitude changes continuously with time and direction of this current gets reversed periodically.
|The alternating current changing magnitude with time and direction periodically.|
Value of alternating current changes with the time between zero and its peak value. There are two different terms to find the value of alternating currents (AC).
We have given all the info and notes about these two in our notes
Measurement of AC:
So to measure of AC, if you think logically then there are two ways to measure alternating current:
1. Component measurement: Measuring the component of the current.
P.s: Component measurement is practically not possible because when we talk about component of electric current it also includes measuring the amount of charge passing in current which is practically not possible to find out. So, therefore, it’s a theoretical method and practically not possible.
2. Effect measurement: Measuring the effect created by AC.
So this method is actually possible because we can measure the effect created due to current and by measuring this we can find what amount or measure of AC current can do to such extent of the effect.
So, therefore, the definition of effect measurement in the terminology of physics would be:
The magnitude of alternating current is the value of steady current which does the same work during time period of one cycle.
Steady current is type of current that does not change its magnitude or direction with time and is constant throughout the time.
I know, it’s a bit confusing so let me clear this for you, suppose a steady current does some work amount ‘X’ in the time period taken by alternating current to complete one cycle. So the magnitude of steady and alternating current will be the same.
Important topics from Alternating currents for boards are L.C.R circuits, Induced EMF, Power Factor, Transformer, AC Circuits and RMS Current.
For 1 marker and MCQ for class 12 boards, conceptual questions from these topics as well as Phasor and LCR circuits diagram related questions can be asked.
All these topics are provided in the notes given below, they are highly in-depth class 12 physics notes of Alternating current so refer to them, it’s more than enough for boards.
This article is a brief summary of chapter 7, Alternating Current for all the derivation related to this chapter and other important things. I have prepared my special handwritten notes. These notes have all the derivation of this chapter and important topics for your board exam 🙂
So do read these notes if you are a class 12th student and preparing for your board exam. These notes are easy to understand. To download them CLICK HERE.