FLUID MECHANICS MCQ SET 5
Q1.The total energy line (TEL) represents:
A) Kinetic head only
B) Pressure head + Velocity head + Datum head
C) Static head
D) Velocity head only
Answer: B) Pressure head + Velocity head + Datum head
Explanation: TEL shows total energy per unit weight of fluid at different points in a flow system.
Q2.The dimension of kinematic viscosity is:
A) LยฒTโปยน
B) LTโปยฒ
C) MLTโปยณ
D) LยณTโปยน
ย
Answer: A) LยฒTโปยน
Explanation: Kinematic viscosity (ฮฝ) = Dynamic viscosity (ฮผ) / Density (ฯ), giving dimension LยฒTโปยน.
Q3.The discharge through an orifice varies as:
A) โhead
B) head
C) headยฒ
D) 1/head
Answer: A) โhead
Explanation: Q=CdA2ghQ = C_d A \sqrt{2gh}; thus discharge is proportional to square root of head.
Q4.The coefficient of discharge (Cd) is:
A) Ratio of actual to theoretical discharge
B) Ratio of theoretical to actual discharge
C) Constant
D) Unity
Answer: A) Ratio of actual to theoretical discharge
Explanation: Cd = Qactual / Qtheoretical; it accounts for energy losses and flow contraction.
Q5.A Pitot tube measures:
A) Static pressure
B) Velocity head
C) Flow velocity
D) Total head
Answer: C) Flow velocity
Explanation: Pitot tube measures stagnation pressure to determine fluid velocity.
Q6.The efficiency of a fluid machine is defined as:
A) Output/Input
B) Input/Output
C) Loss/Input
D) None
Answer: A) Output/Input
Explanation: Efficiency = Useful output energy รท Input energy ร 100%.
Q7.The pressure difference in a Venturi meter is measured by:
A) Manometer
B) Thermometer
C) Barometer
D) Flow nozzle
Answer: A) Manometer
Explanation: The differential manometer connected to the Venturi measures pressure difference between throat and inlet.
Q8.The drag force on a sphere moving through a fluid depends on:
A) Diameter and velocity
B) Fluid density and viscosity
C) Both A and B
D) None
Answer: C) Both A and B
Explanation: Drag force depends on fluid properties (ฯ, ฮผ) and sphere size and velocity.
Q9.The terminal velocity of a particle in a viscous fluid is the velocity at which:
A) Acceleration is maximum
B) Net force is zero
C) Drag is minimum
D) None
Answer: B) Net force is zero
Explanation: Terminal velocity occurs when gravitational and buoyant forces balance viscous drag.
Q10.In a centrifugal pump, the fluid enters the impeller:
A) Radially
B) Axially
C) Tangentially
D) None
Answer: B) Axially
Explanation: Fluid enters the pump impeller axially and leaves radially due to centrifugal action.
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