"A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the
Channel: Doubtnut
Date: 2020-04-05

"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 weighs 8 g/cm3, then the weight of the pipe
 is
(a) 3.6
 kg (b) 3.696 kg (c) 36 kg (d) 36.9 kg"