Resistivity of metals at low temperatures

Question

Two statements are given one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the codes (A), (B), (C) and (D) as given below. 

(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). 
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false and Reason (R) is also false.

Assertion (A): Resistivity of a metal varies non-linearly at very low temperatures.

Reason (R): Resistivity approaches some finite value as the temperature approaches absolute zero.

Answer 1

(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Explanation:

Both the statements are true. Also, because the variation is non-linear, the intercept on the resistivity-temperature graph is non-zero.