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Question
- What is meant by electric current?
- Name and define its unit.
- Which instrument is used to measure the electric current? How should it be connected in a circuit?
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Solution
- (i) Electric current is often termed as .current. and it is represented by the symbol .I. It is defined as the rate of flow of charges in a conductor.
(ii) The electric current represents the amount of charges flowing in any cross section of a conductor (say a metal wire) in unit time. - The SI unit of electric vurrent is ampere (A) The current flowing through a conductor is said to be one ampere, when a charge of one coulomb flows across any cross - section of a conductor in one second.
Hence,
1 ampere = `"1 coulomb"/"1 second" ` - (i) Ammeter is used to measure the current.
(ii) An Ammeter is connected in series with circuit.
(iii) The Ammeter is a low impedance device connecting it in parallel with the circuit would cause a short circuit, damaging the Ammeter or the circuit.
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