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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

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)

e.m.f= energy transferred to charge/charge
€=W/Q ~> W=€Q

S.I unit= Jc^-1 or V

4

Potential Difference (p.d)

p.d= energy transferred to charge/charge
V=W/Q ~> W=VQ

S.I unit= Jc^-1 or V

5

Resistance

Resistance= potential difference/current
R=V/I

S.I unit= ohm

6

Resistivity

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

S.I unit= ohm meter

7

Energy

Energy= power*time
E=p*t

S.I unit= J

8

Power

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

Work done= charge*voltage
W= Q*V

S.I unit= J

10

Total Resistance

Total resistance
R1 + R2 + R3 +... = R

S.I unit= ohm

11

Total Resistance (parallel)

Total resistance (parallel)
1/R1 + 1/R2 + 1/R3 +... = 1/R

S.I unit= ohm