A student performs an experiment to determine the Young's modulus of a wire, exactly`2m` long, by Searle's method. In a particular reading, the student measures the extension in the length of the wire to be `0.8mm` with an uncertainty of `+- 0.05mm` at a load of exactly `1.0kg`, the student also measures the diameter of the wire to be `0.4mm` with an uncertainty of `+-0.01mm`. Take `g=9.8m//s^(2)` (exact). the Young's modulus obtained from the reading is

Options

A. `(2.0 +- 0.3) xx 10^(11) Nm^(-2)`
B. `(2.0 +- 0.2) xx 10^(11) Nm^(-2)`
C. `(2.0 +- 0.1) xx 10^(11) Nm^(-2)`
D. `(2.0 +- 0.5) xx 10^(11) Nm^(-2)`

Answer

B