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Nichrome, manganin and constantan are widely used in wire bound standard resistors because:

Nichrome, manganin and constantan are widely used in wire bound standard resistors because: Correct Answer Very weak dependence of resistivity with temperature

CONCEPT:

Electrical Resistance:

  • The measurement of the opposition of the flow of electric current through a cross-section of the material is called the electrical resistance of that material.
  • It is denoted by R.
  • The relationship between resistance and temperature is given by,


⇒ R = Ro(1 + αΔt)

Where R = resistance at a reference temperature, α = temperature-coefficient of a conductor, and Δ T = changes in temperature

  • For metals, α is positive and for semiconductors, α is negative.
  • Some materials like Nichrome (which is an alloy of nickel, iron, and chromium) exhibit a very weak dependence of resistivity with temperature.
  • Manganin and constantan have similar properties. These materials are thus widely used in wire-bound standard resistors since their resistance values would change very little with temperatures.


EXPLANATION:

  • Some materials like Nichrome (which is an alloy of nickel, iron, and chromium) exhibit a very weak dependence of resistivity with temperature.
  • Manganin and constantan have similar properties. These materials are thus widely used in wire-bound standard resistors since their resistance values would change very little with temperatures.
  • Hence, option 2 is correct.

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