In the determination of Young’s modulus  $(\mathrm{Y}=\frac{4\mathrm{MLg}}{\mathrm{\pi }\text{l}{\mathrm{d}}^2})$  by using Searle’s method, a wire of length L = 2m and diameter d = 0.5 mm is used. For a load M = 2.5 kg, an extension ℓ = 0.25 mm in the length of the wire is observed. Quantities d and ℓ are measured using a screw gauge and a micrometer, respectively. They have the same pitch of 0.5 mm. The number of divisions on their circular scale is 100. The contributions to the maximum probable error of the Y measurement