A wire, 3m in length and 1 mm in diameter at 30 ° C is kept in low...

The change in length of the wire due to change in temperature

$= \alphaLT = 1.2 \times {10}^{- 5} \times 3 \times \left(-170 - 30\right)$

$= - 7.2 \times {10}^{- 3}m$

The change in the length of the wire due to the stretching force

$= \dfrac{FL}{AY} = \dfrac{10 \times 10 \times 3}{0.75 \times {10}^{- 6} \times 2 \times {10}^{11}}$

$= 2 \times {10}^{- 3}m$

The total change in the length of the wire

$= - 7.2 \times {10}^{- 3} +2 \times {10}^{- 3}$

$= - 5.2 \times {10}^{- 3}m = - 5. 2mm$

The negative sign indicates contraction of the wire