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0:00 further ahead we'll be starting with a topic a topic which all of you all are familiar about a topic called to be electricity but under electricity there are two important terms if i speak about the first term electricity the first term when i speak about i can call the word static and the other word which i call will be current now for a student will certainly get confused what exactly electricity means what exactly static
0:45 means what exactly current means the term electricity if i consider is simply called electric charge it's simply called electric charge every physical quantity in physics has to be abbreviated by a symbol electric charge is symbolized by a variable capital q its unit we call an si so call is a system internationally accepted unit and this si unit we consider is called column
1:30 abbreviated as capital c named after physicist charles augustine column so electric charge capital q assign unit coulomb what am i speaking about this electric charge this electric charge yes can be considered to be at rest or this electric charge can be considered to be in motion if i speak about the word static that means we are dealing with studies related to electric charge at rest but when i'm speaking about current electricity what are we studying we are studying about electric charge in motion so the word static stands for stationary
2:16 but the word current stands for motion hence if i want to speak about what do you mean by the term cognitive electricity then for a student to understand the term current electricity what do you say as i told you electricity is electric charge capital keyword symbol a unit coulomb the word current stands for motion of electric charge now any object will set into motion yes it has some energy associated with it likewise for current electricity if i want to speak then what is current electricity it's the energy associated
3:03 with a moving charge so one can ask you what exactly you mean by current electricity what do you mean by current electricity energy associated with a moving charge now when you look at the statement energy associated for a student will get try to understand what exactly mean by electric charge moving electric charge yes we all are familiar about two basic electric charge protons and electrons where do you find that protons to be protons are embedded
3:49 into the nucleus having a charge positive thereby nucleus has a positive charge what about electrons electrons certainly revolve around the nucleus performing uniform circular motion and they have a negative charge so if i speak about electric charge then charges are of two kinds we consider we simply call a proton and an electron if i want to represent proton symbolically how would cochlear weak represent in form of a symbol proton one plus one electron e0 minus one the superscript speaks about
4:37 we consider its mass is considered to be negligible for electron and as a unit mass but what about proton we consider it's positively charged an electron we consider negatively charged so proton positively charged electron negatively charged now when i speak about energy associated with the moving charge then a student should know yes we are speaking about motion of any of these charges whether it's proton or whether it's electron the term current electricity was invented long very long before it was initially tried to put forward by ampere and walter while dissecting a
5:22 frock during those days electrons were not at all discovered thereby they considered to be a proton that's a flow of a charge a positive charge since electrons were no more considered during those days they consider flow of positive charge to be a flow of electric current now when i speak about flow of charge flow of protons but what happens when this protons is flowing yes it has some energy associated with it energy always flows from well to where as a student knows it energy always flows from where to where from a region of high potential to a region of what
6:09 region of low potential so when one wants to speaks about flow of energy yes the energy always flows from vertical from a region of high potential to region of low potential to understand current electricity yes we'll now understand two simple analogues two simple illustrations to understand flow of energy take a simple example suppose if i happen to take a water tank this water tank now i'll consider to be in two ways one having a broader what we consider and one having a narrow width considered
6:55 these two beakers are now connected by a side tube having a stop in between s stands for the stop i have a cylinder a i have a cylinder b what am i trying to do into this to understand concept of what flow of energy as if i told you energies flows from wet aware from high potential to low potential let us consider tank a or the cylinder a consists of water and that water is at a higher level hl stands for higher level let us consider that the beaker b of cylinder b has water which is at the lower level
7:40 now if you consider what is the difference between the two level then yes a student should say sir it is actually the difference in the hydrostatic pressure i'm using the word hydrostatic yes it's a term related to water since there is a difference in potential difference in the level what happens if i happen to open this top yes water starts running from where to where from a to b now when the water starts running the level of a will certainly go on decreasing but what about the level of b will certainly goes on increasing this will go on this will go on this will go on until the two levels become
8:26 equipotential but now if you see this dotted red ink what exactly is dotted reading speaks about yes the two levels are now reached to what restore equipotential so when the water reaches at an equal level yes there is no movement of water that means when the two ends becomes equipotential water does not flow so what was the reason for the water to flow it's the difference in the hydrostatic potential energy this difference has caused water to move from where to where from a to b this is one simple illustration one simple example or an analog to prove
9:12 energy always flows from where to from higher level to lower level take one more basic example suppose if i happen to consider a hot body this hot body is at a high temperature let us consider 80 degree celsius another body if i happen to consider which is at a low temperature 20 degree celsius both these bodies are placed in an isolated surroundings that means considered to be placed in an insulator so that no external heat energy should enter the system not even the heat energy should come out of the system then then in those conditions who will lose the heat energy
9:57 yes a body at a high temperature will certainly lose the heat energy and who is going to gain the heat energy a body is at a low temperature what exactly heat heat a form of energy what exactly the flow of water was a flow of energy if i say heat is a form of energy energy always flows from wet away yes we have learnt it from high potential to low potential over here from higher level to our lower level what do i call over here then from a high temperature to a low temperature once when the two bodies reaches to a common temperature 10 degrees celsius what's going to happen in that case the two bodies will attain
10:44 thermal equilibrium will there be flow of heat energy no will there be flow of water over here no why because the two levels have become equally potential likewise likewise we say a charge has to move and if a charge has to move certainly there will be some energy associated but if i want this charge to move there should be a difference in potential only of a flow of water we call hydrostatic potential difference the flow of heat energy we call the thermal potential difference in case of electricity what we call electric
11:29 potential difference so now if i want to understand motion of charge yes motion of charge there is some energy associated for this energy to move there should be some difference in electric potential difference who provides me this electric potential difference can you tell me who provides this electric potential difference over here you can say yes sir difference in water level only it's a difference in temperature likewise who provides me electric potential difference in simple terms what is a source for electric potential difference source a cell a battery a cell or a battery yes a cellular battery will certainly have
12:15 what an electric potential difference try to take a simple ordinary cell from the market a no we know or an ever ready whatever cells you consider when you happen to take that cell carefully look onto it they will certainly write down onto it 1.5 volt now if in case if i look at a cell yes a cell has one end which is considered to be positive now then we consider to be negative what exactly the positive and i'll consider it to be as the higher level what about the negative and the the lower level that means high potential and low potential likewise you have a difference in water level difference in temperature yes this
13:02 difference we call difference in electric potential difference this electric potential differences of how much 1.5 volt this difference will certainly cause what to flow an electric charge to flow and when this electric charge is flowing it will have some energy associated what kind of energy what kind of energy will be associated for a charge in motion electric charge in motion has some energy certainly it will be called as kinetic energy this kinetic energy so associated with a moving charge simply we call current electricity so if i want to speak about what exactly
13:48 some electricity yes electric charge si unit column electric charge classified into two static and current we consider static rest current and motion we are trying to understand current electricity what did i speak about current electricity energy associated with a moving charge what kind of charges you allowed about it protons and electrons initially which charge we considered protons because electrons were not at all discovered during those days it was protons which was playing a role that's what the physicist used to think this protons were considered to be as the charge which was certainly in motion and when this charge is set into motion
14:35 it will have some energy associated if i want to speak about flow of energy then what causes the flow of energy the energy flows from very well from higher potential to low potential the difference in water level causes water to flow the difference in temperature will certainly cause heat to flow thereby a difference in electric potential difference will certainly cause an electric charge to flow and when this electric charge flows it will have some kinetic energy associated this kinetic energy so associated with the moving charge we call current electricity now when i speak about further ad electric potential difference a source is a cell
15:22 what is going to happen when i take this particular cell and connect it to two metallic plates what's going to happen in that case one end will be positive each other and we consider to be negatively charged yes there is a difference in potential difference we consider and that potential difference will certainly cause charge to flow so today we have certainly spoken about flow of energy and the cost of flow of energy for current we consider is what a cell or a battery certainly this is just a gesture we consider but henceforth certainly whenever we are going to interact the interaction will be in such a way that yes the student should get the concepts properly
16:08 so eagerly waiting to meet you all to work out with you all and to have a better knowledge regarding the topic
