# Electric Current Notes

This is a sample of our (approximately) 3 page long Electric Current notes, which we sell as part of the Physics AS Level Notes collection, a A package written at Manchester High School For Girls Sixth Form in 2013 that contains (approximately) 36 pages of notes across 13 different documents.

### Electric Current Revision

The following is a plain text extract of the PDF sample above, taken from our Physics AS Level Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.

Unit 1: 4 Electric Current

CURRENT AND CHARGE CURRENT IS THE RATE OF FLOW OF CHARGE
∆Q = I∆t

or

I = ∆Q
∆t

Current = change in coulombs time taken

The Coulomb is the unit of charge; One coulomb (C) is deﬁned as the amount of charge that passes in 1 second when the current is 1 ampere. Current is measured in amperes, you can measure it using an ammeter connected in series. NB: Charge of an electron = 1.6 x 10-19 (given in formula booklet)

Charge carriers; Current is due to the passage of charged particles called charge carries (electrons or ions). They can be classiﬁed as conductors (metals), semiconductors and insulators (non-metals).

KIRCHHOFF'S FIRST LAW: the total current entering a junction must equal the total current leaving the junction

POTENTIAL DIFFERENCE POTENTIAL DIFFERENCE IS THE WORK DONE (OR ENERGY TRANSFER) PER UNIT CHARGE V = W Q

Potential difference = work done

charge

The volt is the unit of potential difference; 1 volt = 1 joule per coulomb or 1V = 1JC-1 Potential difference is measured using a voltmeter connected in parallel.

POWER POWER IS THE RATE OF TRANSFER OF ENERGY P=VI

Power = potential difference x current

total energy (J) = power x time

therefore E = VIt

Power is measured in watts; 1W = 1Js-1 PHYSICS AS NOTES

13

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