Define Electric Current ? It's Direction , Nature and S.I Unit
Define electric current. What is the direction of electric current? State and define S.I. unit of electric current. What is the nature of electric current? Give types of current. ELECTRIC CURRENT : Electric current: Electric current is defined as the amount of electric charges flowing through any cross-section of a conductor per unit time. Let charge $Q$ crosses through a cross-section of a conductor in time $t$, then $I = \frac{\text{Total charge flowing (Q)}}{\text{Time taken (t)}}$ $I = \frac{Q}{t} \quad \dots (1)$ If $n$ electrons, each of charge $e$ ($= 1.6 \times 10^{-19}$), cross through a cross-section of a conductor in time $t$, then total charge passing through a cross-section of the conductor is given by, $Q = ne$. Hence, $ I = \frac{Q}{t} = \frac{ne}{t} \quad \dots(2) $ Electric current defined by eqn. (1) is known as steady current. If the net charge $\Delta Q$ crosses the shaded cross-sectional area of the conductor in a time $\Delta t$, then the average electric cur...