Question

The diameter of a sphere is 6 cm. It is melted and drawn in to a wire of diameter 2 mm. The length of the wire is

Options

• 12 m

• 18 m

•  36 m

• 66 m

Answer 1

The diameter of a sphere = 6 cm

Then radius of a sphere`=6/2 cm = 3 cm`

The diameter of a wire = 2 mm

Then radius of wire = 1 mm = 0.1 cm

Now,

Volume of sphere = volume of wire

`4/3 pir^3 = pi r^2 h`

Here,

r = radius

l = length of wire

`4/3 xx 3xx 2 = 0.1 xx 0.1 xx l`

`36 = 0.01 l`

`l = 36/0.01`

To remove the decimal from base we should multiply both numerator and denumerator by 100,

We get,

`l = 3600 = 36m`