Question

Young's modulus of steel is $1.9\times {10}^{11}{\text{N/m}}^2$. When expressed in $\text{CGS}$ units of ${\text{dyne/cm}}^2$, it will be equal to

• A. $1.9\times {10}^{10}$
• B. $1.9\times {10}^{11}$
• C. $1.9\times {10}^{12}$
• D. $1.9\times {10}^{13}$

Answer 1

The correct option is C $1.9\times {10}^{12}$

Given, Young's modulus $Y=1.9\times {10}^{11}{\text{N/m}}^2$
As we know that $1\text{N}={10}^5\text{dyne}$ and $1\text{m}={10}^2\text{cm}$
So, converting the value to $\text{CGS}$ we get
$Y=\frac{1.9\times {10}^{11}\times {10}^5\text{dyne}}{({10}^2{)}^2{\text{cm}}^2}$
$\Rightarrow Y=1.9\times {10}^{12}{\text{dyne/cm}}^2$