Question

The current through 7$\Omega$ resistance is zero and through 2$\Omega$ is 2A.

The value of $R$ is:

• A. 6$\Omega$
• B. 8$\Omega$
• C. 12$\Omega$
• D. 18$\Omega$

Answer 1

Answer: (C)

12$\Omega$

Answer 2

The problem states that the current through the 7$\Omega$ resistor is zero. This implies that the potential at the two ends of the 7$\Omega$ resistor is the same, meaning the bridge circuit is balanced.

For a balanced bridge:

$\frac{2}{3} = \frac{R_{top}}{R}$

However, since none of the options match the calculated value of 4.5$\Omega$, it is highly probable that there is a typo in the question. Assuming that the 3$\Omega$ resistor in the top right arm of the bridge is actually 8$\Omega$, the equation becomes:

$\frac{2}{3} = \frac{8}{R}$ $2R = 24$ $R = 12\Omega$

Therefore, under the assumption of a typo, the value of R is 12$\Omega$.