NEET Physics: Viscosity Practice Questions
15 free multiple-choice questions on Viscosity (Properties of Solids and Liquids) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. If two liquids have the same density, the liquid with higher viscosity will exhibit:
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Correct answer: B — Greater resistance to flow
Since viscosity measures resistance to flow, a higher viscosity implies greater internal friction and thus greater resistance to flow compared to a liquid of the same density.
Q2. If the pressure applied to a liquid is increased, how does its viscosity typically change (assuming constant temperature)?
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Correct answer: B — It increases
Increasing the pressure generally increases the resistance to flow, thus increasing the viscosity of the fluid, provided the temperature remains constant.
Q3. Which of the following physical properties is a measure of the internal resistance to flow of a fluid, which is defined as the ratio of shear stress to the rate of shear strain?
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Correct answer: B — Viscosity
Viscosity is the fundamental property of a fluid that measures its resistance to flow or deformation under an applied shear stress. It is the measure of internal friction within the fluid.
Q4. Which physical property primarily determines the viscosity of a simple Newtonian fluid at constant temperature?
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Correct answer: D — Density
For Newtonian fluids, viscosity is primarily an intrinsic property related to the intermolecular forces resisting flow, which depends heavily on the fluid's density and molecular structure.
Q5. Viscosity is fundamentally a measure of the fluid's resistance to which physical property?
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Correct answer: C — Shear stress
Viscosity is the measure of a fluid's internal resistance to flow, which is directly related to shear stress and shear rate.
Q6. Which of the following fluids generally exhibits the highest viscosity among the common liquids (water, oil, honey) at the same temperature?
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Correct answer: D — Honey
Honey is a highly viscous substance compared to water, oil, and gasoline due to the larger intermolecular forces and structure in honey.
Q7. The force required to maintain a certain flow rate of a viscous fluid is known as:
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Correct answer: C — Shear stress
Shear stress is the force applied parallel to the surface divided by the area, representing the internal friction or resistance experienced by the fluid flow.
Q8. Viscosity of a fluid is fundamentally a measure of its resistance to flow. Which physical property primarily dictates the internal friction within a viscous substance?
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Correct answer: D — Molecular cohesive forces
Viscosity arises from the internal friction between adjacent layers of fluid molecules. This resistance to flow is directly related to the molecular cohesive forces within the substance.
Q9. Which factor is generally the most significant determinant of the viscosity of a liquid?
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Correct answer: B — The molecular weight of the constituents
Viscosity is directly related to the cohesive forces between molecules. The molecular weight and the nature of these interactions (which dictates molecular structure) are the most significant factors.
Q10. When a fluid flows from a wide container to a narrow tube, the resistance to this flow is governed by the fluid's viscosity. If the viscosity of the fluid is high, what is the expected behavior of the flow rate?
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Correct answer: C — The flow rate will decrease
High viscosity means high internal resistance to flow. Therefore, if viscosity is high, the flow rate through the constriction will decrease.
Q11. A fluid that exhibits a constant viscosity regardless of the rate of deformation applied to it is classified as a:
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Correct answer: A — Newtonian fluid
A Newtonian fluid obeys Newton's law of viscosity, meaning its viscosity remains constant regardless of the applied shear rate.
Q12. Which of the following factors primarily increases the viscosity of a liquid?
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Correct answer: C — Increasing intermolecular forces
Increasing intermolecular forces (due to stronger attractive forces between molecules) makes it harder for the molecules to slide past each other, thereby increasing viscosity.
Q13. The force required to maintain a constant flow rate of a fluid through a conduit is directly related to the fluid's:
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Correct answer: A — Viscosity
The force required to overcome internal friction and maintain flow is directly proportional to the fluid's viscosity.
Q14. The shear stress applied to a fluid during flow is directly proportional to which property of the fluid?
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Correct answer: B — Viscosity
Shear stress (the force applied per unit area causing flow) is directly related to the viscous forces within the fluid, making viscosity the key property determining the flow behavior under shear.
Q15. Which of the following physical quantities is the SI unit of viscosity?
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Correct answer: C — Poise (P)
The SI unit of dynamic viscosity (or absolute viscosity) is Pascal-second (Pa·s), which is equivalent to Poise (P) in CGS units.
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