Q. How many minimum number of 2$\ \Omega$ resistance can be connected to have an effective resistance of 1.5$\ \Omega$?
A) 3
B) 2
C) 4
D) 6
Explanation
(c) Let the circuit be as shown
Equivalent resistance between A and B is
$\frac{1}{R} = \frac{1}{2} + \frac{1}{(2 + 2 + 2)} = \frac{2}{3}$
$R = \frac{3}{2} = 1.5\Omega$
Therefore, 4 resistances are required.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.