A hollow iron pipe is 21 cm long and its external diameter is 8 cm. I…

Question

A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weights 8 g/cm3, then the weight of the pipe is:

Accepted Answer

Option B. 3.696 kg. Answer & Solution Answer: Option B Solution: & External\, radius = 4\,cm & Internal\, radius = 3\,cm & Volume\, of\, iron & = ( 227 × [ ( 4 )^2 - ( 3 )^2 ] × 21 )cm^3 & = ( 227 × 7 × 1 × 21 )cm^3 & = 462\,cm^3 & Weight\, of\, iron = ( 462 × 8 )gm & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,…