Practice question

Given: A wire of length 3 m and resistance 6 Ω is stretched to 6 m . What is the new resistance? Formula: Volume constant: l A = l' A' Rightarrow A' = A/2. Substitution & Calculation: New resistance: R' = rho l'/A' = fracrho (2l)A/2 = 4 rho l/A = 4R = 4 × 6 = 24 Ω . Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.