Q39 of 40 Page 1

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

OR


A metallic sphere of radius 4.2 cm is melted and recast into the shape of a cylinder of radius 6 cm. Find the height of the cylinder.


Diameter = 1 cm


Radius = 0.5 cm


Volume of rod = π × r2 × h




Length of wire = 18 m = 1800 cm


Volume of rod





Thickness


= 0.67 mm


OR


Radius of sphere = r = 4.2 cm


Volume of sphere



Radius of cylinder = R = 6 cm


Height = H


Volume = π × r2 × h



Volume of sphere = Volume of cylinder




⇒ H = 2.74 cm


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