Pressure In A Fluid - Practice Questions & MCQ

• Fluids- 

Fluids are the substances which began to flow when an external force is applied to it.

Fluids examples are liquids and gases.

Fluids don't have their own shape but they take shape of the containing vessel.

In Hydrostatic branch we study fluids which are at rest with respect to containing vessel.

While in Hydrodynamics we study fluids which are in motion with respect to containing vessel. For example study of flowing water from the tap comes under Hydrodynamics.

          Ideal fluids-  Assumption

1. It is Incompressible- Means the density and the specific volume of the fluid do not change during the flow.

2. It is Non-viscous- Layers of fluids does not exert any tangential force (especially friction force)  on each other. And A true "non-viscous" fluid would flow along a solid wall without any slowing down because of friction.

• Pressure- 

1. Normal force exerted by liquid/fluid at rest per unit Area of the surface is called pressure of a liquid/fluid.

          If F is the normal force acting on a surface area A in a container with liquid.

then pressure exerted by liquid on this surface is

$$
P=\frac{F}{A}
$$

2. Units of pressure is $N / \mathrm{m}^2$ or Pascal (S.I) and $d y n e / \mathrm{cm}^2$ (C.G.S)
3. The dimension of pressure is $M L^{-1} T^{-2}$
4. Atmospheric pressure- The pressure exerted by the atmosphere is called atmospheric pressure. 1 atm is the value of atmospheric pressure on the surface of the earth at sea level.

And $1 \mathrm{~atm}=1.01 \times 10^5 \mathrm{~N} / \mathrm{m}^2=1.01 \times 10^5 \mathrm{Pascal}=1.01 \mathrm{bar}=760 \mathrm{torr}$
So Relation between bar and Pascal is $1 \mathrm{bar}=10^5 \mathrm{~Pa}$