Question

please give the answer fast.......​

Answer 1

Answer:

Given,

Diameter of wire = 3 mm

= $\frac{3}{10} cm$

Hence, one round of wire covers 3/10 cm of the height of the cylinder.

Length of cylinder = 12 cm

Wire will cover entire length of cylinder hence, number of rounds are:

Rounds $\frac{3}{10}$ cm is covered in = 1 round

Rounds 1 cm is covered in = 1 × $\frac{10}{3}$ rounds

Rounds 12 cm is covered in = 12 × $\frac{10}{3}$ rounds

= 40 rounds

Length of wire required to complete one round = Circumference of cylinder

= 2πr

= 2π $(\frac{10}{2})$

= 10π cm

Length of wire required to cover whole cylinder = 10π × 40

= 400π cm

= 400 × 3.14

= 1256 cm

Density of copper = 8.88 g/cm³

Diameter of wire = $\frac{3}{10} cm$

Radius of wire = $\frac{3}{10}$ × $\frac{1}{2} cm$

= $\frac{3}{20} cm$

Volume of wire = πr² × length

= π $(\frac{3}{20})^{2}$ × 1256

= $\frac{pi*9*1256}{400}$

= $\frac{35494.56}{400}$

= 88.73 cm³

Density of wire = $\frac{Mass}{Volume}$

So, Mass = Density × Volume

= 8.88 × 88.73

= 787.83 gm

Length of wire = 1256 cm

Mass of wire = 788 gm

Hope it helps