Current, Charge, SI units

Asked by  | 4th Apr, 2013, 03:54: PM

Expert Answer:

The directed flow of negative charges (i.e. electrons) through a wire is called an electric current. A current is said to be flowing if a closed link has been provided for the electrons. This link is called the electric circuit. An electric circuit provides a continuous path for the electrons to flow, and hence constitute an electric current.

The magnitude of an electric current is defined as the amount of electrons passing through a cross-sectional area of the wire within a given interval of time.

i.e., Current =

Or, 

Where, I ? amount of current

Q ? amount of electrons flowing through a cross-section

t ? time taken

The SI unit of current (I) is taken as ampere (A), named after the great physicist, Andre Marie Ampere (1775 ? 1836).

Since, the SI unit of charge is coulomb (C) and that of time is second (s), we define 1 ampere (A) as,

Answered by  | 4th Apr, 2013, 11:49: PM

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