Question

Length of a wire is 5 m. When a force is applied, its length changes by 0.2m. Calculate
strain in wire.
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Answer 1

Given:

• Initial length of wire is 5 metres.
• Length change is 0.2 metres.

To find:

• Strain in wire ?

Calculation:

Strain is a physical quantity (without any units) defined as the ratio of change in dimensions to the initial dimensions of the object.

Let strain be denoted by $\sigma$

$\therefore \sigma = \dfrac{change \: in \: length}{initial \: length}$

$\implies\sigma = \dfrac{\Delta L}{L}$

$\implies\sigma = \dfrac{0.2}{5}$

$\implies\sigma = 0.04 \:$

So, strain in wire is 0.04 .

• Please note : STRAIN DOESN'T HAVE ANY UNIT !