Question

What is the equivalent resistance between A and B in the given combination of resistances (Fig.)?

Options

• 1 Ω

• 2 Ω

• 3 Ω

• none of these

Answer 1

1 Ω

Explanation:

In a balanced Wheatstone bridge no current flows through the middle resistor, so the circuit reduces to two parallel branches of two 1 Ω resistors in series (2 Ω each), giving 2 Ω in parallel with 2 Ω, which equals 1 Ω. Option 2 Ω is wrong because it ignores the parallel combination of the two branches.