Question

Explain the construction meter bridge.

Answer 1

Meter bridge:

A meter bridge is an electrical instrument that is used to find the value of an unspecified resistance. It works on the principle of Wheatstone Bridge.

Steps to construct a meter bridge are given below:

1. Take two metal strips that are bent to form an L shape. The metal should be a high conductor of electricity.
2. Take a 1-meter long wire of a uniform cross-section area. The wire's resistance should not depend on temperature (example: Manganin, Constantan).
3. Fix this wire between the metal strips.
4. Take the unknown resistance R and fix it at the other end of the metal strip. Similarly, take a resistance box S and fix it at the other end of the other metal strip, and connect the unknown resistance and the resistance box using a rectangular metal strip of the same material.
5. Place a meter scale below the 1-meter long wire.
6. Take a galvanometer whose one end is attached to the rectangular metal strip and the other end has a jockey that will slide over the metal wire.
7. Finally, from the two points where the 1-meter long wire was fixed, attach a wire which will contain the battery or current source and a key to switch on-off the circuit.

R-Unknown Resistance, S-Resistance Box, $K_1$-Switch, $\in$-Battery, G- Galvanometer, D-Jockey.