Hydraulics & Fluid Mechanics
The normal stress is same in all directions at a point in a fluid

only when the fluid is incompressible and has zero viscosity
When there is no motion of one fluid layer relative to an adjacent layer
only when the fluid is frictionless
irrespective of the motion of one fluid layer relative to an adjacent layer

ANSWER DOWNLOAD EXAMIANS APP

Hydraulics & Fluid Mechanics
For laminar flow in a pipe of circular cross-section, the Darcy’s friction factor f is

inversely proportional to Reynolds number and directly proportional to pipe wall roughness
inversely proportional to Reynolds number and indpendent of pipe wall roughness
directly proportional to pipe wall roughness and independent of Reynolds number
directly proportional to Reynolds number and independent of pipe wall roughness

ANSWER DOWNLOAD EXAMIANS APP