A sphere of radius 7 cm is melted and drawn into a wire of radius 0.21 cm. The length of the wire is (approximately) -

9.33 cm 9.33 × 104 cm 311 cm 154 cm

9.33 × 104 cm

Volume of sphere = volume of cylinder (wire) \(\frac{4}{3}\) \(\pi \) r3 =  \(\pi \)r2h  ⇒ \(\frac{4}{3}\) (7)3 =(0.21) (0.21) × h ⇒ h = \(\frac{4\;×\;7\;×\;7\;×\;7}{3\;×\;21\;×\;21}\) × 104  Length of wire (h) = 9.33 × 104 cm