Assertion (A): As a wire is stretched to four times its length, its resistivity becomes four times, such that resistance also increases.
Reason (R): \( R = \frac{\rho A}{l} \) where symbols have their usual meaning.
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false
Solution:
Assertion (A) is false because resistivity is an intrinsic property of the material and does not change with stretching, only resistance changes. Reason (R) is false because the correct formula for resistance is \( R = \frac{\rho l}{A} \).
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