A straight wire $15 m$ long is subjected to a tensile stress of $2000 kgf/c{m}^2$.  Elastic modulus is 

$1.5 x {10}^6 kgf/c{m}^2.$  Coefficient of linear expansion for the material is 

• • 1

    $40$

  • 2

    $80$

  • 3

    $120$

  • 4

    $160$