 Now, let us come back to these kind of errors, random and systematic. Now, tell me what could be the example of systematic error? Yeah, no, no, no, no, it will have precision. I mean, you are using an instrument to measure something. Suppose, you are measuring length using a varnier jumper. What could be the systematic error? Lack of accuracy. No, no, no, it is wrong. I am sorry, but you do it. And you need the value of saving. I mean, I will have the value of saving. Decision is same thing. Decision is there. Yeah, right. Lack of accuracy. See, the definition of systematic is this. Systematic errors are the error which can remove systematically using step by step manner if you perform the experiment you can remove the systematic error that is the definition of systematic error. Now can you give me examples of it 0 error, write down 0 error parallax error, what else suppose you are angry all the time okay even that can cause the systematic error so there will be a step don't be angry right. Sir won't be angry. No if you are angry, if you are angry then probably you have this habit of measuring the smaller length slightly more when you are angry. Sir what is the subtlety of anger? Somebody slapped you. That's that. Okay so there can be many systematic errors there can be like you know there are some okay in your textbook it is systematically written these systematic errors. There are three parts of the systematic error write down instrumental error, instrumental error, second part imperfect experimented procedure, third one is the personal error you have personal bias, personal error okay so instrumental error we already discussed they are write down 0 error they are like 0 for example 0 errors, 0 error is the example of instrumental error okay suppose you have an instrument okay which always you know that it is giving faulty readings okay the systematic error so how you should remove that, replace the instrument are you getting it it is a systematic error which you can correct it by changing the instrument itself or if you know that there is a 0 error how much is 0 error you can just calibrate it. Also like why are heating up in electrical experiment? Why are heating up in electrical experiment suppose your room is having high temperature okay and somehow you are inside the room alive and doing the experiment everything will get expanded are you getting it so that step will be conduct this experiment at 35 or 30 degrees less than 30 degrees like that that could be the step to remove that error so there that every systematic error has a step to remove it fine so this is instrumental error imperfect procedure what could be the example of imperfect, parallax error you have this habit of looking thing like that so there will be parallax error getting it you have this habit of looking from one eye close the other eye so you have just seen right the object moves object shifts so we need to remove that so what could be the step of that look from both the eyes look from the above like that so that is why these steps of conducting experiments are there in your lab records personal errors suppose you are doing the experiment with your enemy you will find so step could be don't do the experiment with your enemy I mean it may sound like a very funny thing but there you know these things are they can cause the error okay so personal error could be anything we humans are very complicated it could be any damn thing in fact in fact imperfect procedure or experimental condition the parallax error is personal error by the way it's not procedure it's a personal error I think we have said first parallax is imperfect procedure no it is from the personal point of view how you conduct the experiment can cause a personal error okay imperfect procedure could be if you are using if you are conducting the experiment at 100 degree Celsius but it should be conducted at 20 degree Celsius that is imperfect procedure but whatever is the error arising from your personal the way you are conducting experiment is the personal error getting it personal error should be independent of what is a what is the instrument how you're tightening it and things like that personal error should be only you only only you could blame random error random errors write down random errors are the errors which cannot be removed random errors cannot be removed these can arise write down these errors can arise due to these errors can arise due to random and unpredictable due to random and unpredictable fluctuations in experimental conditions getting it these errors can arise due to random and unpredictable fluctuations in the experimental conditions okay what could be these fluctuations fluctuation in power voltage fluctuation in voltage you cannot calculate how much fluctuation it's a random thing there can be some there can be wind that suddenly starts blowing getting it that can cause random error alright so any random event can cause the random error which you cannot quantify how much is the error and you cannot have a step to remove these errors alright so that give me few examples there are not many examples one is random fluctuation in voltage what could be the other example wind and all of all that fluctuation in the experimental condition random fluctuation in experimental condition you can say that you know you can you can say that I will take care of fluctuations by using a better voltage source and things like that okay but you'll never be able to eliminate it that's what my point is you can minimize it but you can't make it zero okay you'll say that okay I'll conduct the experiment in a vacuum chamber okay but perfect vacuum can't be achieved getting it similarly you can say that I use a constant voltage source what if one electron which is traveling in the wire starts moving randomly because of whatever reason it collided inside with the another nucleus inside the wire and it is not moving as per what you want to be it is random okay you cannot make sure that electron dodges each and every atom inside the wire it will get collided okay so you cannot remove these errors you can just minimize it minimizing means you're managing them okay what else what do you think other random earthquake there is an earthquake you are in the middle of experiment you will continue doing experiment okay I'll conduct the experiment then only I'll die what if it's very small and you were doing some experiment with a pendulum or something yeah correct so that's all it is random fluctuation and experiment that's common to fluctuation only okay there when you why you have screw gauge and 1-year caliper both to measure the length why can't you just use 1-year caliper not just screw gauge okay the normal scale you have can you measure more than 1 mm less than 1 mm using that you cannot you can say you know you can roughly say though you can say that this is 1 mm so if my length is here somewhere I'll what I'll say I'll say that it is 0.45 I can argue why not 0.44 I'm getting it so you are never sure if it is 0.4 or 0.5 you can say it is between 0.4 and 0.5 okay but accuracy of precision is not there less than 1 mm less than 1 mm accuracy is not there in your scale I'm getting it so there is an error in the second decimal point yes or no right you don't know when you say 0.4 4 you don't know whether it is 0.47 0.43 0.45 there is uncertainty in the second decimal place okay so this is random error because of the nature of instrument itself the instrument which you are using is not accurate enough to give you the true reading it's not systematic because you cannot remove it you can use a different instrument suppose rather using scale you say okay I'll use 1 mm caliber 1 mm caliber has accuracy till second decimal point now third decimal point has error getting it then you say I'll use screw gauge till 3 decimal point but the fourth decimal point has error you cannot eliminate it understood and you can't even quantify it here you can quantify how much is the error imperfect procedure instrument error you know exactly how much is the 0 error 0 error is 1 mm so you take into account of 1 mm but if I say the random error is 1 mm you don't know whether you to add or subtract are you getting it these are random error it could be both sides you don't know fine so this is this is called least counter right now even for some means you remove the random fluctuation suppose you are somewhere where there is no fluctuation in anything okay but you can never remove least counter never ever okay so this is the kind of random error which we need to manage this least counter we must manage all these can be eliminated okay but then we need to manage this counter for example if I measure the length okay if I measure the length let's say 0.4 meter with a device which can only measure up to first decimal point okay so what I'll say I'll say my measurement is lying between 0.4 plus minus 0.1 meters are you getting it this is an error it can be point it is definitely more than 0.3 but less than 0.5 okay so it is one thing to talk about number okay when I have to say some number okay for example let's say pi pi has a fixed value no error why because you have not measured it it's a constant pi is a constant fixed value no error 2 is a number which is a constant you have not measured it no error but if you are measuring something let's say I'm measuring length I'm measuring mass time every measurement has at least this one this error least counter which you cannot remove okay all right that is why you have these instruments more accurate and accurate instrument like 1M caliper is there screw gauge is there there are instruments which measure more accuracy than screw gauge also they are probably up to four places of their decimal it is accurate but fifth decimal places not accurate okay so there is a difference between this reading 2.000 meter and if I say 2.0 meter there is a difference between these two this is accurate absolutely there is some place this is accurate only first the way you write there is a difference