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Properties of Fluid MCQs – Part 1

15 questions. Tap an option to check it instantly, then read the solution.

Practice SSC JE and other civil engineering exam questions on the fundamental properties of fluids: viscosity (Newton's law, Newtonian vs non-Newtonian fluids, dynamic and kinematic viscosity units), surface tension and capillarity (droplets, bubbles, capillary rise and depression), bulk modulus and compressibility, specific weight, density, specific gravity and specific volume, and pressure types (absolute, gauge, vacuum). Tap an option to check it, then open the full explanation for each question.

Question 1Easy
According to Newton's law of viscosity, the shear stress of a fluid element layer is directly proportional to the:
Full explanation

Answer: D. rate of shear strain

Newton's law of viscosity states that shear stress is directly proportional to the rate of shear strain (or velocity gradient), giving τ = μ(du/dy).

Question 2Easy
The shear stress at a point in a liquid is found to be 0.02 N/m². The velocity gradient at this point is 0.20 s⁻¹. What will be the viscosity of the liquid (in poise)?
Full explanation

Answer: D. 1

Using τ = μ(du/dy), μ = 0.02 / 0.20 = 0.1 Pa·s. Since 1 Pa·s = 10 poise, μ = 0.1 × 10 = 1 poise.

Question 3Easy
If the velocity of the fluid does NOT change with respect to time, the flow is said to be a/an:
Full explanation

Answer: D. steady flow

Flow is steady when fluid velocity and other properties at any fixed point do not change with time (∂v/∂t = 0).

Question 4Easy
Which of the following property of water makes the raindrops to form roughly spherical structure?
Full explanation

Answer: B. surface tension

Surface tension causes a liquid surface to contract to the minimum possible surface area, which for a given volume is a sphere.

Question 5Easy
______ is that branch of science which deals with behaviour of the fluids (liquids or gases) at rest as well as in motion.
Full explanation

Answer: D. Fluid mechanics

Fluid mechanics is the broad branch of science that investigates the behavior of liquids and gases both at rest and in motion.

Question 6Easy
If the specific weight of a certain liquid is 5000 N/m³, then calculate the specific volume (in m³/N).
Full explanation

Answer: D. 0.0002

Specific volume in m³/N is the reciprocal of specific weight: v = 1 / γ = 1 / 5000 = 0.0002 m³/N.

Question 7Easy
Surrounding atmospheric pressure is taken as datum to find ______.
Full explanation

Answer: B. gauge pressure

Gauge pressure is measured using local atmospheric pressure as datum. Note: This exam question was cancelled by the commission because vacuum pressure also uses atmospheric pressure as datum.

Question 8Easy
How does the atmospheric pressure (AP) vary with respect to the altitude?
Full explanation

Answer: B. AP decreases with increase in altitude

Atmospheric pressure decreases with increasing altitude because the weight and density of the overlying air column decrease.

Question 9Medium
A hydraulic press has a ram of cross-section area 30 cm × 30 cm and a plunger of cross-section area 4 cm × 4 cm. Find the force F required to lift the weight W = 30 kN.
Full explanation

Answer: B. 533.33 N

By Pascal's law, F / A_plunger = W / A_ram. Therefore F = 30 kN × (16 / 900) = 533.33 N.

Question 10Easy
It is found that the weight of liquid is 15 N which measures 6 litres. Calculate its specific weight.
Full explanation

Answer: A. 2500 N/m³

Specific weight is weight divided by volume: γ = 15 N / (6 × 10⁻³ m³) = 2500 N/m³.

Question 11Easy
Calculate the approximate mass density of oil with 4.5 m³ of volume and 40 kN of weight (Consider g = 10 m/s²).
Full explanation

Answer: A. 889 kg/m³

Mass is weight divided by gravity: m = 40,000 / 10 = 4000 kg. Density ρ = 4000 / 4.5 ≈ 888.89 kg/m³ ≈ 889 kg/m³.

Question 12Easy
If a person studies about a fluid which is at rest, the study is called:
Full explanation

Answer: D. fluid statics

The study of fluids at rest (in static equilibrium without relative motion) is called fluid statics.

Question 13Easy
2 litres of an oil weigh 16 N. Calculate the specific gravity of the oil. Consider the density of water to be 998 kg/m³.
Full explanation

Answer: A. 0.816

Density of oil is W / (gV) = 16 / (9.81 × 0.002) = 815.5 kg/m³. Specific gravity S = 815.5 / 998 ≈ 0.816.

Question 14Medium
A capillary tube of diameter 4 mm is dipped into a liquid of specific gravity 0.6. The liquid rises in the tube by 20 mm, making an angle of contact of 0° with the tube. Determine the surface tension of the liquid in contact with air and the glass tube.
Full explanation

Answer: B. 0.12 N/m

Using h = 4T cosθ / (ρgd), T = hρgd / (4 cosθ) = 0.02 × 600 × 10 × 0.004 / 4 = 0.12 N/m.

Question 15Easy
What is the standard atmospheric pressure at sea level?
Full explanation

Answer: B. 1.013 bar

Standard atmospheric pressure at sea level is 1.01325 bar (101.325 kPa or 760 mm of Hg).