Question

Equivalent resistance between A and B will be [CPMT 1981]
A) 2 ohm B) 18 ohm C) 6 ohm D) 3.6 ohm

Answer 1

Two resistors of 10 ohm connected to points B and C can not be part of any closed path between A and D, so these resistors will not be the part of circuit between point A &D. Now 6 resistors are connected between A & D and equivalent resistance can easily found as

10+(10+10)||(10+10)+10 = 30.

So equivalent resistance is 30 ohm.