Hydraulics And Fluid Mechanics - Study Mode

[#161] Choose the correct relationship
Correct Answer

(B) dynamicviscosity = kinematicviscosity x density

[#162] If the velocity is zero over half of the cross-sectional area and is uniform over the remaining half, then the momentum correction factor is
Correct Answer

(C) 2

[#163] Units of surface tension are
Correct Answer

(A) energy/unit area

Explanation

Solution: Surface tension is indeed a measure of the energy required to increase the surface area of a liquid by a unit amount, and it is commonly expressed in units of energy per unit area (such as N/m or dyn/cm). Option B (distance) is not correct, and option C (both of the above) is not accurate in this context. So, for the specific field of Hydraulics and Fluid Mechanics, the correct answer is option A.

[#164] Dimensions of surface tension are
Correct Answer

(B) ML 0 T -2

Explanation

Solution: We know that Surface Tension (σ) = Force / Length Step-by-Step Dimensional Analysis: 1. Dimensional Formula of Force (F): - Force = Mass × Acceleration - Acceleration = Length / Time² = LT -2 - So, Force = M × LT -2 = MLT -2 2. Dimensional Formula of Length (L): - L = L 1 3. Dividing Force by Length: - σ = (MLT -2 ) / L - σ = ML (1-1) T -2 = ML 0 T -2 Thus, the correct dimensional formula for surface tension is ML 0 T -2 , making Option B the correct choice .

[#165] Which of the following instruments is used to measure flow on the application of Bernoulli’s theorem
Correct Answer

(D) all of the above

Explanation

Solution: Bernoulli's theorem states that in an ideal fluid flow, the sum of pressure energy, kinetic energy, and potential energy per unit volume remains constant along any streamline. This principle can be applied to various types of flow measurement devices to determine the flow rate of a fluid. The instruments mentioned in the options are commonly used to measure flow based on Bernoulli's theorem. Venturimeter: A venturimeter is a device used to measure the flow rate of a fluid in a pipe by utilizing the principle of Bernoulli's theorem. It consists of a converging section followed by a throat and then a diverging section. The pressure difference between the converging and diverging sections is used to determine the flow rate. Orifice Plate: An orifice plate is another flow measurement device based on Bernoulli's theorem. It consists of a thin plate with a hole (orifice) in it, placed in the pipeline. The pressure difference across the orifice is used to calculate the flow rate. Pitot Tube: A pitot tube is used to measure fluid velocity based on Bernoulli's theorem. It has a pointed end that faces the fluid flow, and a pressure difference is created between the pointed end and the open end of the tube, which is used to determine the fluid velocity. All of the above instruments (Venturimeter, Orifice Plate, and Pitot Tube) are utilized to measure flow by applying Bernoulli's theorem. They exploit the relationship between fluid pressure, velocity, and elevation to determine the flow rate accurately. Therefore, the correct answer is Option D: all of the above .