Question

Young's modulus of steel is $1.9 \times 10^{11}\, N \,m^{-2}$. When expressed in $CGS$ units of dynes $cm^{-2}$, it will be equal to ($1 \,N = 10^5$ dyne, $1\, m^2 = 10^4\, cm^2$)

• 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

Answer: (C)

$1.9 \times 10^{12}$

Answer 2

Dyne and Newton, both are units of force. While Dyne is specified in $C-G-S$(Centimeter - Gram - Second) unit system, Newton is specified in modern $SI$ unit system which gives the relationship Young's Modulus between stress and strain. It is used to measure hardness of material.