Ys = \(\frac{F}{A}\) \(\frac{I}{∆I_s}\) and Yr = \(\frac{F}{A}\)\(\frac{I}{∆I_r}\)
For same force applied to wires made of steel and rubber of same length and same area of cross section.
ΔIs < ΔIr
\(\frac{Y_s}{Y_r}\) = \(\frac{ΔI_r}{Δl_s}\) > 1
∴ Ys > Yr
