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if there are n particles per unit volume each having charge q and moving with speed v then current through cross sectional area A is |
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Answer» Answer:ELECTRIC current is defined to be the rate at which charge flows. A large current, such as that used to start a truck engine, moves a large AMOUNT of charge in a SMALL time, whereas a small current, such as that used to operate a hand-held calculator, moves a small amount of charge over a long period of time. In equation form, electric current I is defined to be I = Δ Q Δ t , where ΔQ is the amount of charge passing through a given area in time Δt. (As in previous chapters, INITIAL time is often taken to be zero, in which case Δt = t.) (See Figure 1.) The SI unit for current is the ampere (A), named for the French physicist André-Marie Ampère (1775–1836). Since I = ΔQ/Δt, we see that an ampere is one coulomb PER second: 1 A = 1 C/s Not only are fuses and circuit breakers rated in amperes (or amps), so are many electrical appliances. Explanation: |
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