A pipe of diameter three cm is replaced by one of the same length but of diameter six cm.If the pressure difference between the ends of the pipe remains the same,by what factor is the rate of flow of a viscous liquid through it changed?
A)2
B)4
C)8
D)16
E)32

Question

Quizplus · Accepted Answer

According to the Poiseuille's law, the rate of flow through a pipe is proportional to the fourth power of its radius. Hence, the rate of flow through the new pipe with twice the radius will be 2^4=16 times that of the old pipe. Thus, the answer is D) 16.

A Pipe of Diameter Three Cm Is Replaced by One