Q1.The dimensions of pressure is:
- A.[M-1L2T-2]
- B.[ML-1T]
- C.[M-1L-2T-2]
- D.[ML-1T-2]
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Correct answer: D. [ML-1T-2]
Pressure, defined as force per unit area, has dimensions [ML⁻¹T⁻²], derived from force [MLT⁻²] divided by area [L²].
Fluid Dynamics, Elasticity and Surface Tension MCQs for MDCAT
29 practice MCQs on fluid flow, Bernoulli's principle, viscosity, elasticity, stress and strain, and surface tension. Every question has the correct answer and an explanation.
Start free — 20 questionsFluid Dynamics, Elasticity and Surface Tension is part of the MDCAT Physics syllabus. This page collects Fluid Dynamics, Elasticity and Surface Tension MCQs in the style of past MDCAT papers — below are 12 of them with answers and explanations, and the full set of 29 questions is in the HighYield MDCAT QBank.
This chapter covers: fluid flow, Bernoulli's principle, viscosity, elasticity, stress and strain, and surface tension.
Fluid Dynamics, Elasticity and Surface Tension MCQs with answers
Q2.The density of blood is:
- A.Less than water
- B.Nearly equal to water
- C.Greater than water
- D.Three times that of water
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Correct answer: B. Nearly equal to water
The density of blood is nearly equal to that of water, only slightly greater (approximately 1060 kg/m³ compared to water's 1000 kg/m³).
Q3.Flow speed of the fluid through a non uniform pipe increases from 1 m/sec to 3 m/sec. If change in P.E. is zero, then pressure difference between two points will be: (density of the fluid = 1000 kg/m3)
- A.1000 N/m2
- B.9000 N/m2
- C.8000 N/m2
- D.4000 N/m2
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Correct answer: D. 4000 N/m2
Using Bernoulli's equation with zero change in potential energy, the pressure difference equals ½ρ(v2² − v1²) = ½ × 1000 × (9−1) = 4000 N/m².
Q4.For the horizontal pipe, the fluid inside it is flowing horizontally then Bernoulli’s equation can be written as
- A.P + ρv2 = constant
- B.2P + ρv2 = constant
- C.P + 2ρv2 = constant
- D.2P + 2ρv2 = constant
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Correct answer: B. 2P + ρv2 = constant
For horizontal flow (no change in height), Bernoulli's equation simplifies to P + ½ρv² = constant along the streamline.
Q5.Mass flow per second of the fluid is given by:
- A.ρAv
- B.Av
- C.ρv Av
- D.ρ
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Correct answer: A. ρAv
The mass flow rate of a fluid through a pipe is given by ρAv, the product of density, cross-sectional area and flow speed.
Q6.In Bernoulli’s equation the term ρv2 is called:
- A.K.E. per unit volume
- B.K.E.
- C.K.E. per unit area
- D.K.E. per unit length
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Correct answer: A. K.E. per unit volume
In Bernoulli's equation, the term ½ρv² represents the kinetic energy per unit volume of the moving fluid.
Q7.The ratio of tensile strength to tensile strain is called
- A.Modulus of elasticity
- B.Bulk Modulus
- C.Young’s Modulus
- D.Shear Modulus
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Correct answer: C. Young’s Modulus
Young's Modulus is defined as the ratio of tensile stress to tensile strain within the elastic limit of a material.
Q8.Strain energy in a deformed energy is stored in the form of:
- A.Elastic Energy
- B.Potential Energy
- C.Plastic Energy
- D.Kinetic Energy
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Correct answer: B. Potential Energy
Strain energy stored in a deformed elastic material is stored in the form of potential energy, released when the deforming force is removed.
Q9.A gas containing ‘N’ number of molecules of a gas having mass of each molecule ‘m’ is in a cubic container having length of each side ‘a’. What is the density of gas contained in cube?
- A.N/a2
- B.m/a3
- C.Nm/a3
- D.Na3/m
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Correct answer: C. Nm/a3
The density of the enclosed gas is calculated as total mass divided by volume: (N × m)/a³, since the cube has volume a³.
Q10.A gaseou mixture contains 9.6% NH3, 22.6% N2 and 67.8% H2 gases. If the total pressure Is 5O atm, then the partial pressure of H2 is
- A.67.8 x100 / 50
- B.50 x 100 / 100
- C.67.8 X 50/ 100
- D.67.8 +50/ 100
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Correct answer: C. 67.8 X 50/ 100
To find the partial pressure of H2, we need to calculate the pressure contributed by H2 gas based on its percentage in the mixture. Given: Percentage of H2 = 67.8% Total pressure = 50 atm To find the partial pressure of H2, we multiply the percentage of H2 by the total pressure and divide by 100: Partial pressure of H2 = (67.8 × 50) / 100 Or Partial pressure of H2 = 33.9 atm
Q11.In an elastic collision, the total kinetic energy
- A.Dissipates after collision
- B.Increases after the collision
- C.Reduces after the collision
- D.Before and after collision remains the same
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Correct answer: D. Before and after collision remains the same
In an elastic collision, the total kinetic energy before the collision is equal to the total kinetic energy after the collision, meaning that kinetic energy is conserved throughout the process.
Q12.The square root of the ratio of elasticity to mass density is equal to:
- A.Force
- B.Product of frequency and wavelength
- C.Co-efficient of viscosity
- D.Refractive index
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Correct answer: B. Product of frequency and wavelength
The correct answer is the product of frequency and wavelength. This relationship arises from the wave equation, where the speed of sound in a medium is given by the square root of the ratio of the elastic modulus (elasticity) to the mass density. Therefore, the square root of this ratio yields the speed of sound, which directly relates to how waves propagate through solids.Option A, Force, is incorrect because force is not a derived quantity from elasticity and mass density in this context. Option C, Co-efficient of viscosity, pertains to fluid dynamics and is unrelated to the elastic properties of solids. Lastly, Option D, Refractive index, is a concept in optics and does not apply to the relationship expressed in the question.
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