Question

On which principle does the Meter bridge work?

Answer 1

Wheatstone bridge and Meter Bridge

1. Wheatstone bridge is a circuit arrangement to measure an unknown resistance with the help of three known resistances similarly,
2. A meter bridge also called a slide wire bridge is a device used to find the unknown resistance of a conductor with the help of some known resistance.

Working principle of Meter Bridge-

1. A meter bridge is based on the principle of the Wheatstone bridge which is based on the principle of zero deflection for which the ratio of resistance P to Q in one arm is equal to the ratio of resistance R to S in the other arm then the current through the middle arm of the circuit will be zero.
2. Consider the diagram of the Wheatstone bridge as shown below. It consists of four resistances P, Q, R, and S with a battery of EMF E.

Thus, in the null deflection condition, the current through the galvanometer is zero, and the potential at terminals B and D is the same.

So, $\frac{P}{Q}=\frac{R}{S}$.

Hence, Meter Bridge or Slide Wire Bridge is based on the principle of the Wheatstone bridge.