Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard
Home > Electric current and electrical circuits

Electric current and electrical circuits - (Concept)

Electric current and electrical circuits

  • Let us consider two metallic conducting balls which are charged at different potential are hanged using a non-conducting insulating wire.As we know that air is an insulator so, no charge transfer takes place

  • If we join both the metallic balls by using a conducting metallic wire then charge will start flowing from the metallic ball at higher potential to the one at lower potential.

  • This flow of charge will only stop when the potential difference between them will be zero.

  • If anyhow we can maintain the potential between the metallic balls through a cell or battery, we will always get constant flow of the charge in metallic wire which is connecting the two conducting balls.

  • This flow of electric charge in metallic wire due to the electric potential difference between two conductors used is called electric current.

  • So, Electric current can be expressed by the amount of charge flowing through a particular area per unit time.

  • Or we can say that it is the rate of flow of electric charges (say electrons) in a conductor (for example copper or Aluminium wire).

  • So, if a net charge Q, flows across a cross-section of a conductor in time t, then the current I through the cross-section is expressed as -
                                                          $I=\frac{Q}{t}$
    The S.I. unit of electric current is Ampere, which is denoted by - A

 

  • Current is measured by an instrument which is called an ammeter. It is connected in series in a circuit through which the current is to be measured.

  • An electric circuit - It is a continuous and closed path of an electric current. For example, the figure given below shows a typical electric circuit comprising a cell, an electric bulb, an ammeter A and a plug key K.

                                                            

 

Please note that the current flows in the circuit from the positive terminal of the cell to the negative terminal of the cell through the bulb and ammeter

  • So, the conventional direction of electric current is from the positive terminal of the cell to the negative terminal through the outer circuit or we can say that the conventional direction of electric current is in the direction of the flow of positive charged carriers.

Exam Chapter
JEE FOUNDATION Electricity
Concepts List
« Previous Concept List Next »
Exams
Articles
Questions