APSC Legal Metrology: Paper 2 MCQ on Principle of Continuity

A fluid is flowing through a horizontal pipe. When the pipe is constricted, then

(A) both velocity and pressure increase
(B) both velocity and pressure decrease
(C) velocity increases and pressure decreases
(D) velocity decreases and pressure increases

Explanation:

• According to the Principle of Continuity:
  In a pipe, when the cross-sectional area decreases (i.e., the pipe is constricted), the velocity of the fluid increases to conserve mass flow rate.
• According to Bernoulli’s Principle:
  In a flowing fluid, when the velocity increases, the pressure decreases.

Thus, in a constricted section of a horizontal pipe:

• Velocity increases
• Pressure decreases

Hence, the correct option is (C)