Gauge factor of a strain gauge is defined as the ratio of the fractional change in resistance \(\left(\frac{\Delta R}{R}\right) \) to the fractional change in length \(\left(\frac{\Delta L}{L}\right) \). A metallic strain gauge with a gauge factor 2 has a resistance of 100 Ω under unstrained condition. An aluminum foil with Young's modulus Y = 70GN / m2 is installed on the metallic gauge. Keeping the foil within its elastic limit, a stress of 0.2GN / m2 is applied on the foil. The change in the resistance of the gauge will be closest to