Question

In the previous question Two wire $A$ and $B$ have equal lengths and are made of the same material, but the diameter of $A$ is twice that of wire $B$. Then, for a given load

• A. Youngs modulus of $A$ is twice that of $B$
• B. Youngs modulus is same for both $A$ and $B$
• C. $A$ can withstand a greater load before breaking than $B$
• D. $A$ and $B$ will withstand the same load before breaking

Answer 1

Answer: (B), (C)

The correct options are
B Youngs modulus is same for both $A$ and $B$
C $A$ can withstand a greater load before breaking than $B$

$force=stress\times area$

$force\alpha area$

So,

$F\alpha (d{)}^2$

So, $\frac{F_A}{F_B}=\frac{(d_A{)}^2}{(d_B{)}^2}={\left(\frac{d_A}{d_B}\right)}^2=(2{)}^2=4(\therefore \frac{d_A}{d_B}=2)$

So,

A can withstand a greater load than B and since material of A and B are same they have same young's modulus.