Question

A wire strain gauge element subjected to a strain has a gauge factor of 2, a resistance of 125 ohms and is of 1m length. For a change in length of the wire by 0.005 m , the change in the resistance in $\Omega$ will be

• A. 0.25
• B. 0.5
• C. 1.25
• D. 2.5

Answer 1

The correct option is C 1.25

$G.F=\frac{\frac{dR}{R}}{\frac{dL}{L}}$

$G.F=2$

$R=125\Omega$

$\Delta l=0.005m$

$\Delta R=R\times G.F\times \Delta l=125\times 2\times 0.005$

$=1.25\Omega$