Q. The effective resistance of two resistors in parallel is $\frac{12}{7}\Omega.$ If one of the resistors is disconnected the resistance becomes $4\ \Omega.$ The resistance of the other resistor is
A) $4\ \Omega$
B) $3\ \Omega$
C) $\frac{12}{7}\ \Omega$
D) $\frac{7}{12}\ \Omega$
Explanation
(b) $\frac{7}{12} = \frac{1}{4} + \frac{1}{R} \Rightarrow R = 3\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.