A steel wire of length 20 cm and uniform cross-section `1mm^(2)` is tied rigidly at both the ends. If the temperature of the wire is altered from `40^(@)C` to `20^(@)C`, the change in tension. [Given coefficient of linear expansion of steel is `1.1xx10^(5) .^(@)C^(-1)` and Young's modulus for steel is `2.0xx10^(11) Nm^(-2)`]

Explanation

The change in the wire of length l when wire is cooled by temperature `Deltat` is given by
`Deltal=lprop Deltat`
or `Deltal//l=propDeltat`
where , `prop` is the coefficient of linear expansion. Change in the tension of the wire when it is cooled is given by
`F=YADeltal//l=YApropDeltat`
`=(2.0xx10^(11))xx(10^(-6))xx(1.1xx10^(-5))xx(40^(@)-20^(@))`
44 N