| English | Electric current |
|---|---|
| Bahasa Melayu | Arus elektrik |
| 中文 | 电流 |
Definition
The rate of flow of electric charge through a conductor (current = charge ÷ time); measured in amperes (A).
In exam terms
Electric current is the rate of flow of electric charge through a conductor. It is a base quantity with the symbol I and the SI unit ampere (A), where 1 A = 1 C s⁻¹.
The defining relationship is I = Q ÷ t, where Q is the charge that flows in coulombs (C) and t is the time in seconds (s). For example, if a charge of 12 C flows past a point in 4 s, the current is I = 12 C ÷ 4 s = 3 A. Conventional current is taken to flow from the positive to the negative terminal of a source, which is opposite to the actual direction of electron flow in a metal.
Do not confuse it with charge
Do not confuse current with charge. Charge Q is the total amount of electricity that has flowed, measured in coulombs (C), while current I is how fast that charge flows, measured in amperes (A).
Current is charge per unit time, so a large charge delivered slowly can give a small current.
Keep it separate too from potential difference, which is the energy per unit charge that drives the current, not the flow itself. In Paper 2 this is asked as define electric current (rate of flow of charge) or calculate the current, charge or time using I = Q ÷ t.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)