Question 57

A solid copper sphere of radius 9 cm is melted and reformed into a wire of radius 1 mm. What will be the length of this wire? (Take π = 22/7)

Solution

Radius of sphere = $$R = 9$$ cm

Let length of wire = $$h$$ cm and radius of wire = $$r = 0.1$$ cm

Volume of sphere = Volume of wire

=> $$\frac{4}{3} \pi (R)^3 = \pi (r)^2 h$$

=> $$\frac{4}{3} \times (9)^3 = (0.1)^2 h$$

=> $$h = 12 \times 81 \times 100$$ cm

=> $$h = \frac{972 \times 100}{100} = 972$$ metres

Share on Whatsapp Share on Whatsapp

Create a FREE account and get: