Question

Assertion : If a current flows through a wire of non-uniform cross-section, potential difference per unit length of the wire in the direction of current is same at different points.
Reason : V = iR and current in the wire is same throughout.

• 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: (D)

(A) is false but (R) is true

Current through the wire at every point is same. But the wire is of non-uniform cross section . The value of R is not same for every infinitesimal element $\therefore$ P.D. across the infinitesimal length is not same for the entire wire.