Flashcards in Electricity (equations) Deck (11)

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1

## Charge

###
Charge=Current*Time

Q=I*t

S.I unit= As^-1 or C

2

## Current

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Current=Charge/Time

I=Q/t

Current=Cross-sectional area * number of free elections per unit volume * charge on an electron * mean drift velocity

I=Anev

S.I unit= Cs^-1 or A

3

## Electromotive Force (e.m.f)

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e.m.f= energy transferred to charge/charge

€=W/Q ~> W=€Q

S.I unit= Jc^-1 or V

4

## Potential Difference (p.d)

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p.d= energy transferred to charge/charge

V=W/Q ~> W=VQ

S.I unit= Jc^-1 or V

5

## Resistance

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Resistance= potential difference/current

R=V/I

S.I unit= ohm

6

## Resistivity

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Resistivity= (resistance*cross-sectional area)/length of wire

P=(RA)/l

S.I unit= ohm meter

7

## Energy

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Energy= power*time

E=p*t

S.I unit= J

8

## Power

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Power= voltage*current

P=V*I

Power= (current)^2 *resistance

P=I^2 *R

Power= (voltage)^2 /resistance

P=V^2 /R

S.I unit= Js^-1 or W

9

## Work done

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Work done= charge*voltage

W= Q*V

S.I unit= J

10

## Total Resistance

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Total resistance

R1 + R2 + R3 +... = R

S.I unit= ohm

11