Question

What is the balance condition used to find the variable resistor Q?

Options

• \[\frac{P}{R} = \frac{Q}{S}\]

• \[P + Q = R + S\]

• \[\frac{P}{Q} = \frac{R}{S}\], which gives \[Q = \frac{PS}{R}\]

• \[P \times Q = R \times S\]

Answer 1

Since the bridge is balanced, the balance condition applies: \[\frac{P}{Q} = \frac{R}{S}\]. Rearranging this equation gives \[Q = \frac{PS}{R}\], which allows the unknown variable resistor Q to be calculated using the known values of P, R, and S.