• # question_answer A solid sphere of radius 6 cm is melted into a hollow cylinder of uniform thickness. If the external radius of the base of the cylinder is 5 cm and its height is 32 cm, find the uniform thickness of the cylinder. A)  2 cm                           B)  3 cm         C)  1 cm    D)  3.5 cm

(c): Let the internal radius of the cylinder = r Then the volume of sphere = volume of hollow cylinder $\Rightarrow$   $\frac{4\pi {{.6}^{3}}}{3}=\pi h({{5}^{2}}-{{r}^{2}})$ $\Rightarrow$   $\frac{864\pi }{3}=32\pi (25-{{r}^{2}})$ $\Rightarrow$   ${{r}^{2}}=16=r=4\,cm$ So thickness of the cylinder = 5 ? 4 = 1 cm