Question

Which material is used for meter bridge wire and why?

Answer 1

Wheatstone bridge:

1. If any component is connected in an electric circuit with unknown resistance then that resistance value can be calculated using the Wheatstone bridge circuit.
2. A Wheatstone bridge is an electrical bridge consisting of two branches of a parallel circuit joined by a galvanometer, in which one branch has unknown resistance.

Meter bridge:

1. The length of wire used in the meter bridge network has a length of one meter with a uniform cross-sectional area. Hence an electric bridge with a one-meter wire that works on the principle of Wheatstone's network Wheatstone's meter bridge.
2. Materials with a low-temperature coefficient of resistance make the resistance of wire unchanged with an increase in temperature due to the flow of current.
3. Alloys used like constantan and Ni-chrome are used in meter bridges as they satisfy the specific property.
4. The setup consists of unit-length wire stretched and clamped between two thick metallic strips bent at right angles. Across the two gaps between the strips, resistors are connected.

Explanation

1. Alloys that are resistant to corrosion and have a low-temperature coefficient of resistance like wires of nichrome, manganin, and constantan are used in a meter bridge.
2. These alloys can hold a high melting point up to 1400° C.