Question

On applying a stress of $20\times {20}^{8}N/m^2$, the length of the perfectly elastic wire is doubled .Its young modules will be

• A. $40\times {10}^{8}N/m^2$
• B. $20\times {10}^{8}N/m^2$
• C. $10\times {10}^{8}N/m^2$
• D. $5\times {10}^{8}N/m^2$

Answer 1

The correct option is B $20\times {10}^{8}N/m^2$

Young's modulus of elasticity
$Y=\frac{stress}{strain}$
$Y=\frac{F}{\Delta l/L}$
$Y=20\times {10}^8$ $[\Delta l=L]$