# Electric Current

Show/Hide Sub-topics (Current of Electricity | A Level)

Electric Current is the rate of flow of charge through a particular cross sectional area with respect to time.

• Units for current is ampere (A)
• 1 A = 1 $C \, S^{-1}$

$$I = \frac{Q}{t}$$

, where

• I = current,
• Q = charge,
• t = time

Instantaneous Current

$$I = \frac{dQ}{dt}$$

The charge that passes through a given point is the product of the steady current flowing past the point and the time during which the current flows.

• Unit of charge: coulomb (C)
• One coulomb is the quantity of charge that flows through a point when a steady current of one ampere flows for one second.

The conventional current direction is the direction in which positive charges effectively move.

In metals, it is the negative charge that flows and hence the conventional current and the negative charge(electrons) flow in opposite direction.