. What is (a) the highest, and
(b) the lowest, total resistance that can be secured by the combination of four coils of resistances 4,8,12 and 24
Sol. The highest resistance can be secured (or obtained) by connecting all the four coils in series. In this case:
R = R1 + R2 + R3 + R4
R = 4 + 8 + 12 + 24
Thus, the highest resistance which can be secured is 48 ohms.
(b) The lowest resistance can be secured by connecting all the four coils in parallel. In this case:
Thus, the lowest resistance which can be secured is 2 ohm.