Food Processing Unit Operations Multiple Choice Questions on “Fluid Statics and Fluid Dynamics”
1. The force per unit area in a fluid is called as __________
a) differential pressure
b) fluid pressure
c) dynamic pressure
d) absolute pressure
Answer: b
Clarification: The force per unit area in a fluid is called as fluid pressure. Since the fluid does not have any shape, the forces can be exerted in all directions such as gravitational force, external force on the fluid.
2. Which principle explains the buoyant force of a fluid?
a) Archimedes principle
b) Pascal’s principle
c) Bernoulli’s Principle
d) Newton’s second law of motion
Answer: a
Clarification: Archimedes principle states that the object partially or fully submerged in a fluid will experience a buoyant force which is equal to the fluid weight in which object is displaced.
3. Hydraulic system works on the basis of ____________
a) Archimedes principle
b) Pascal’s principle
c) Bernoulli’s Principle
d) Newton’s second law of motion
Answer: b
Clarification: Hydraulic system works on the basis of Pascal’s principle. This principle states that when pressure is applied to a closed system of fluid, the pressure is transmitted to every part of the fluid and also to the walls of the container in which fluid is enclosed.
4. Are these statements about the Fluid mechanics true?
Statement 1: Fluid mechanics is a branch in chemistry that involves study of fluids.
Statement 2: Fluid mechanics can be divided into 2 major categories.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: c
Clarification: Fluid mechanics is a branch in physics that involves study of fluids such as liquids, plasma and gases. Fluid mechanics can be divided into 2 major categories. They are fluid statics (study based on fluids at rest) and fluid dynamics (study based on fluids in motion).
5. Which principle is used in designing the wings of airplanes?
a) Archimedes principle
b) Pascal’s principle
c) Bernoulli’s Principle
d) Newton’s second law of motion
Answer: c
Clarification: Bernoulli’s Principle is used in designing the wings of airplanes. According to the law of aerodynamics called Bernoulli’s principle, fast moving air has low pressure than slow moving air which has high pressure, so therefore pressure above wings is lower compared to pressure below the wings and this creates the lift in the plane that powers it to fly upwards.
6. Which of the following statements about applications of Pascal law in daily life are precise?
- Statement 1: It is used in hydraulic pumps and hydraulic press.
- Statement 2: It is not used in braking system in the vehicles.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: a
Clarification: The applications of Pascal law in daily life is that it is used in hydraulic pumps and hydraulic press. It is also commonly used in in braking system in the vehicles where a fluid called brake fluid is used to transmit the pressure from the brake pedal to the all the vehicle wheels.
7. Who is the father of fluid mechanics?
a) Stephen Prokofievitch Timoshenko
b) Ludwig Prandtl
c) Singh Kapany
d) Samuel Colville Lind
Answer: b
Clarification: Ludwig Prandtl is called as the father of fluid mechanics. Stephen Prokofievitch Timoshenko is father of engineering mechanics. Singh Kapany is the father of fiber optics. Samuel Colville Lind is father of chemical kinetics.
8. What are applications of fluid statics?
a) Barometers, anemometer
b) Manometers, anemometer
c) Manometers, hygrometer
d) Manometer, barometers
Answer: d
Clarification: Manometer, barometers are used in measuring the pressure of the fluid based on the fluid state mechanism. Anemometer is used in measuring the wind speed and also the direction of the wind. Hygrometer is used to measure the humidity.
9. Fluid in static condition has shear stress.
a) True
b) False
Answer: b
Clarification: A fluid in static condition has no shear stress. The shear stress is known as force per unit area that is acting parallel to the inconsiderable surface element. It is mainly caused by the friction between fluid molecules due to viscosity of the fluid.
10. What causes the turbulence in fluid flow?
a) Kinetic energy
b) Pressure
c) Force
d) Potential energy
Answer: a
Clarification: During the flow of the fluid, the excessive kinetic energy that is present in the fluid causes the turbulence which overpowers the resistance of fluid. The turbulence is reduced by reducing Reynolds number.