Question

Choose the correct circuit which can achieve the bridge balance.

• A.
• B.
• C.
• D.

Answer 1

Answer: (A)

Answer 2

The condition for a Wheatstone bridge to be balanced is:
$\frac{R_1}{R_2} = \frac{R_3}{R_4}$,
where $R_1, R_2, R_3$, and $R_4$ are the resistances in the respective branches of the bridge.
Analyzing each circuit:
1. In Circuit (1): The ratio $\frac{R_1}{R_2}$ is not equal to $\frac{R_3}{R_4}$.
2. In Circuit (2): Similarly, the ratios are not equal.
3. In Circuit (3): The ratios are not balanced, and hence the bridge does not balance.
4. In Circuit (4): The ratio of resistances satisfies the balance condition:
$\frac{10 \, \Omega}{15 \, \Omega} = \frac{10 \, \Omega}{15 \, \Omega}$.
Therefore, the bridge is balanced in this configuration. Hence, the correct answer is Circuit (4).