Question

A wire of $10m$ long and $1mm$${}^2$ area of cross section is stretched by a force of $20N$. If the elongation is $2mm$, the young's modulus of the material of the wire (in pa) is

• A. 1 x 10${}^9$
• B. 2 x 10${}^{-9}$
• C. 1 x 10${}^{11}$
• D. 1 x 10${}^{12}$

Answer 1

Answer: (C)

1 x 10${}^{11}$

$A={10}^{-6}{m}^2$

$0.002=\frac{10\times 20}{{10}^{-6}\times y}$

$y={10}^{11}N/m^2$