Question

Assertion : Material used in the construction of a standard resistance is constantan or manganin
Reason : Temperature coefficients of constantan and Magnanin are very small

• 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

Answer 1

Answer: (A)

Both (A) and (R) are true and (R) is the correct explanation of (A)

The $\alpha$ of manganin and constantan is almost equal to zero implying that the resistance doesn't change much with change in temperature which is highly essential for construction of standard resistances.