Question

A steel wire is suspended vertically from a rigid support. When loaded with a weight in air, it expands by La and when the weight is immersed completely in water, the extension is reduced to $L_w$. Then relative density of the material of the weight is

• A. $\frac{L_a}{L_w}$
• B. $\frac{L_w}{L_a}$
• C. $\frac{L_w}{L_a-L_w}$
• D. $\frac{L_a}{L_a-L_w}$

Answer 1

The correct option is D $\frac{L_a}{L_a-L_w}$

$L_a=\frac{V\rho g}{A}\frac{L}{y}$
$L_W=\frac{V(\rho -\sigma )g}{A}\frac{L}{y}$