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Electric charge, Meaning (SPM Physics)

A basic property of matter that causes it to experience a force in an electric field; measured in coulombs (C).

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EnglishElectric charge
Bahasa MelayuCas elektrik
中文电荷

Definition

A basic property of matter that causes it to experience a force in an electric field; measured in coulombs (C).

Electricity

In exam terms

Electric charge, symbol Q, is a basic property of matter that causes it to experience a force in an electric field. It is measured in coulombs (C) and is related to current by Q = It, where I is current and t is time.

One coulomb is the charge that passes a point when a current of 1 A flows for 1 s. Charge is carried by electrons (negative) and protons (positive).

Example of correct use: a current of 2 A flowing for 3 s transfers a charge of Q = It = 2 A × 3 s = 6 C.

Do not confuse it with…

Do not confuse electric charge with electric current. Charge Q is the amount of electricity, measured in coulombs; current I is the rate of flow of charge, I = Q/t, measured in amperes. A large charge can pass slowly (small current) or quickly (large current) depending on the time taken.

In Paper 2, questions may ask you to calculate the charge from current and time, or to define the coulomb; be clear that current is the rate of flow, not the charge itself.

Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)

Frequently asked questions

What is the unit of electric charge?
The coulomb (C). One coulomb is the amount of charge that passes a point when a steady current of one ampere flows for one second.
How is charge related to current?
Charge equals current multiplied by time, Q = It. Rearranged, current is the rate of flow of charge, I = Q/t.
What carries electric charge in a wire?
Free electrons, which carry negative charge, drift through the metal. Conventional current is taken to flow in the opposite direction to the electron flow.

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