Fluid Mechanics Quiz

The SI unit of kinematic viscosity (υ) is:

• m²/s

• kg/m·s

• m/s²

• m³/s²

Kinematic viscosity of air at 20°C is given to be 1.6 × 10⁻⁵ m²/s. Its kinematic viscosity at 70°C will approximately be:

• 2.2 × 10⁻⁵ m²/s

• 1.6 × 10⁻⁵ m²/s

• 1.2 × 10⁻⁵ m²/s

• 3.2 × 10⁻⁵ m²/s

For a Newtonian fluid:

• Shear stress is proportional to shear strain

• Rate of shear stress is proportional to shear strain

• Shear stress is proportional to the rate of shear strain

• Rate of shear stress is proportional to the rate of shear strain

The dimension of surface tension is:

• ML⁻¹

• L²T⁻¹

• ML⁻¹T¹

• MT⁻²

The SI unit of dynamic viscosity is:

• Poise

• Pascal-second

• Joule-second

• Newton-second

The flow in which the velocity vector is identical in magnitude and direction at every point for any given instant is called:

• Uniform flow

• Non-uniform flow

• Steady flow

• Unsteady flow

The device used for measuring very small pressure differences is:

• Bourdon tube

• Manometer

• Micromanometer

• Inclined tube manometer

The ratio of the inertial force to viscous force is known as:

• Reynolds number

• Froude number

• Weber number

• Mach number

In an open channel flow, the Froude number is the ratio of:

• Inertial force to gravitational force

• Velocity of flow to wave velocity

• Gravitational force to pressure force

• Pressure force to viscous force

Cavitation in a hydraulic machine occurs when:

• Pressure becomes higher than atmospheric pressure

• Pressure becomes lower than vapor pressure

• Flow velocity decreases suddenly

• Temperature decreases suddenly