1.resistors of 6 ohms and 18 ohms are connected in series to a 72 volt source find a) current through 6 ohm b)

current through the 18 ohms, c) and the effective resistance.





2. solutions for a, b, and c with a parrallel connection.

1.resistors of 6 ohms and 18 ohms are connected in series to a 72 volt source find a) current through 6 ohm b)
Series:


Add up the restance.





Rt = (6 + 18) ohms





Rt = 24ohms





V = IR





V/R = I





a) I = 3 amps





Current at R1 = Current at R2 in series.





b) I = 3amps





c) Rt = 24 ohms








Parallel:





Voltage at R1 = voltage at R2





a) V/R = I





72/6 = 12amps at the 6ohm resistror





b)





72/18 = 4amps at the 18ohm resistor





c)





Rt = 1 / (1/R1) + (1/R2)





Rt = 1/ (1/6ohms) + (1/18ohms)





Rt = 1/ (2/9ohms)





Rt = 9/2 ohms





Rt = 4.5 ohms





Shortcut for two:





Rt = (R1 + R2) / (R1 x R2)
Reply:1.


a) current through 6 ohm = 72/(6 + 18) = 3 A


b) current through the 18 ohms =


72/(6 + 18) = 3 A


c) the effective resistance = 24Ω





2.


a) current through 6 ohm = 72 V/6 Ω = 12 A


b) current through the 18 ohms =


72/18 = 4 A


c) the effective resistance = 72 V/16 A = 4.5Ω