Question

Calculate $I$ for the given circuit diagram.

• A. 10 A
• B. 5 A
• C. 2.5 A
• D. 20 A

Answer 1

Answer: (A)

It is a balanced Wheatstone bridge.
Hence no current flows through resistance of arm $BD$ and the resistance of arm $BD$ is ineffective.
$\therefore \frac{R_{AB}}{R_{BC}}=\frac{R_{AD}}{R_{DC}}
\Rightarrow \frac{5\,\Omega}{5\,\Omega}=\frac{5\,\Omega}{5\,\Omega}$
Resistance of arm $ABC = 5 \,\Omega + 5 \,\Omega = 10 \,\Omega$ Resistance of arm $ADC = 5\,\Omega + 5 \,\Omega = 10\,\Omega$ The effective resistance between $A$ and $C$ is