JEE Main 2026 Physics question
A string A of length 0.314 m and Young's modulus 2 × 10¹⁰ N/m² is connected to another string B of length and Young's modulus both twice of those of A. This series combination of strings is then suspended from a rigid support and its free end is fixed to a load of mass 0.8 kg. The net change in length of the combination is mm. (radius of both the strings is 0.2 mm and acceleration due to gravity = 10 m/s²) (Mass of both strings is to be neglected as compared to the mass of the load)
Answer: (B)
Solution
F = 8 N, A = π(0.2×10⁻³)² = 1.257×10⁻⁷ m². Δ = / ≈ 1 mm;
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