1) During Searle's experiment, zero of the vernier scale lies between $3.20\times 10^{-2}$ m and $3.25\times 10^{-2}$ m of the main scale. The 20th division of the vernier scale exactly coincides with one of the main scale divisions. When an additional load of 2 kg is applied to the wire, the zero of the vernier scale still lies between $3.20\times 10^{-2}$ m and $3.25\times 10^{-2}$ m2 of the main scale but now the 45th division of the vernier scale coincides with one of the main scale divisions. The length of the thin metallic wire is 2m and its cross-sectional area is $8\times 10^{-7}$ m. The least count of the vernier scale is $1.0\times 10^{-5}$ m. The maximum percentage error in the YOung's modulus of the wire is A) 5 B) 4 C) 3 D) 2 Answer: Option BExplanation:$Y=\frac{F/A}{\frac{\triangle l}{l}}, \triangle l=25\times 10^{-50}m$ $Y=\frac{F}{A}.\frac{l}{\triangle l}$ $\frac{\triangle Y}{Y}\times 100=\frac{10^{-5}}{25\times 10^{-5}}\times100=4$ %
