Question

A metallic solid of volume $630m^3$ melted and drawn into the form of a wire of height $21$ m. Find the radius of the wire. (Use $\pi =3$)

• A. $\sqrt{12}$ m
• B. $\sqrt{11}$ m
• C. $\sqrt{10}$ m
• D. $\sqrt{13}$ m

Answer 1

Answer: (C)

$\sqrt{10}$ m

Let the wire is of the shape of the right circular cylinder.
Therefore, volume of the cylinder = $\pi r^{2}h$
630 = $3\times r^2\times 21$
$r^2=\frac{630}{3\times 21}$
$r^2=10$
Squaring on both the sides, we get
$r=\sqrt{10}$ m