Question

A copper rod of diameter 1cm and length 8cm is drawn into a wire of length 18m uniform thickness. Find the thickness of the wire.

Answer 1

the wire is in cylindrical in shape:-

therefore
:- formula to find volume of cylinder is :- $\pi r^{2} h$
therefore diameter is :- 1 so radius is 1/2=0.5
now volume of initial rod = volume of final rod

$\pi r^{2} h$ = $\pi r^{2} h$
pi and pi gets cancelled
(0.5)² x 8 = 18 x y
y= (2.5*8)/18
y= 10/9

Answer 2

Answer:

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Step-by-step explanation:

$\underline\green{Volume \: of \: copper \: rod }$ = π r² h

$= > \frac{22}{7} \times \frac{1}{2} \times \frac{1}{2} \times 8 \\ \\ = > \frac{44}{7} \: \: {cm}^{2}$

If 'r' is the radius of the wire then

$\underline\green{it's \: volume}$ = π r² h

:. The volume of rod is equal to the volume of the wire

$\frac{22}{7} \: {r}^{2} \times 18 \: m = \frac{44}{7} \: {cm}^{2}$

${r}^{2} \: = \frac{44}{7} \times \frac{7}{22} \times \frac{1}{1800}$

${r}^{2} \: = \frac{1}{900} \\ \\ r \: = \sqrt{ \frac{1}{30} }$

$\huge\pink{r \: = \: 0.0333... \: cm}$

:. $\underline\green{Thickness \: (d) }$ = 2 × 0.03

$\huge\bold\orange{===>}$ 0.06 cm.

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