Question

An N-type semiconductor strain gauge having nominal resistance of $1000\Omega$ and a gauge factor of -200 is subjected to a compressive strain of 500 microstrain. The new value of the resistance of the strain gauge is:

• A. $1010\Omega$
• B. $1100\Omega$
• C. $990\Omega$
• D. $900\Omega$

Answer 1

The correct option is B $1100\Omega$

$\because$ Change in resistance of the gauge is given by

$\Delta R=R\times G\times ϵ$

$\Delta R=100\times (-200)\times -500\times {10}^{-6}$

[$\because$ Strain is taken negative because it is compressive]

$\Delta R=100\Omega$

Since the given strain gauge is N-type semiconductor strain gauge hence it's resistance get increases due to compressive strain.

$R=R+\Delta R=1000+100=1100\Omega$