Question 1

Which of the following devices operates on the principle of Pascal's law?

Accepted Answer

Pascal's law states that pressure applied to an enclosed fluid is transmitted undiminished to every portion of the fluid and the walls of the containing vessel. Hydraulic lifts, hydraulic brakes, and hydraulic presses operate on this principle.

Question 2

What is the SI unit of coefficient of viscosity?

Accepted Answer

The SI unit of coefficient of viscosity is Pascal-second ($Pa \cdot s$) or Newton-second per square meter ($N \cdot s/m^2$), also called Decapoise.

Question 3

According to Stokes' law, the terminal velocity ($vt$) of a small spherical body falling in a viscous medium is directly proportional to:

Accepted Answer

According to Stokes' law formula $vt = \frac{2}{9}\frac{r^2(\rho - \sigma)g}{\eta}$, the terminal velocity is directly proportional to the square of the radius ($r^2$) of the spherical body.

Question 4

Bernoulli's theorem is a statement of the conservation of:

Accepted Answer

Bernoulli's theorem is based on the principle of conservation of energy for an ideal fluid undergoing streamline flow.

Question 5

The SI unit of surface tension is:

Accepted Answer

Surface tension is defined as force per unit length ($T = F/L$). Therefore, its SI unit is Newton per meter ($N/m$).

Mechanical Properties of Fluids