Q64 / 90 · JEE Main 2022 (29 Jul Shift 2) · Physics

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Alloys such as constantan and manganin are used in making standard resistance coils.

Reason R: Constantan and manganin have very small value of temperature coefficient of resistance.

In the light of the above statements, choose the correct answer from the options given below.

  • Correct answer
    A
    Both A and R are true and R is the correct explanation of A
  • B
    Both A and R are true but R is NOT the correct explanation of A.
  • C
    A is true but R is false.
  • D
    A is false but R is true.

Solution

The alloys manganin and constantan are used for making standard resistance coils as they have high resistivity, low-temperature coefficient of resistance, ability to attain good resistance values in small size. Their resistance value would change very little with temperature.

Thus, both A and R are true and R is the correct explanation of A.

Hence, the correct answer is option: 'A'.

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