. How can three resistors of resistances
2 ohm, 3 ohm, and 6 ohm be connected to give a total resistance of
(a) 4 ohm, and
(b) 1 ohm?
Sol. In order to obtain a total resistance of 4 from three resistors of 2 ,3 and 6 .
Firstly, connect the two resistors of 3 and 6 in parallel to get a total resistance of 2 which is less than the lowest individual resistance.
(ii) Then the net R from parallel connection is connected in series with the remaining 2 Q resistor to get a total resistance of 4 Q. This is because in series combination:
R = R1+ R2
R = 2 + 2
R =4 ohm
The arrangement of three resistors of 2,3 and 6 which gives a total resistance of 4 ohm can now be represented as follows :
(b) In order to obtain a total resistance of 1 ohm from three resistors of 2 ohm, 3 ohm and 6ohm, all the three resistors should be connected in parallel. This is because in parallel combination: