Q. Two resistances are joined in parallel whose resistance is $3/5\Omega$. One of the resistance wire is broken and the effective resistance become $3\Omega$.The resistance in ohm of the wire that got broken was
A) 4/3
B) 2
C) 6/5
D) 3/4
Explanation
(d) $R_{p} = \frac{R_{1}R_{2}}{R_{1} + R^{2}} = \frac{3}{5}and\ R_{1} = 3\Omega$ then
$\frac{3 \times R_{2}}{3 + R_{2}} = \frac{3}{5}\ or\ 15R_{2} = 9 + 3R_{2}$
or $12R_{2} = 9\ or\ R_{2} = \frac{3}{4}\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.