In Biot-Savart law, the circulation taken about any path enclosing the vortex filament is____

A)
Zero
B)
Constant
C)
Path-dependent
D)
Depends on the local strength

Correct Answer :   Constant


Explanation : The circulation taken about any path enclosing the vortex filament is a constant. This is true for a straight as well as curved filament. (Kelvin’s circulation theorem).