Properties of Solids and Liquids — NEET Physics MCQs with answers

Properties of Solids and Liquids is a Class 11 Physics chapter in the NEET (UG) syllabus. NEET720 has 1,077 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.

Topics covered

Buoyancy and Floatation · Elasticity · Fluid statics · Fluid dynamics · Viscosity · Surface tension · Thermal expansion · Calorimetry and change of state · Heat transfer and thermal radiation · Fluid pressure · Pascal's law · Archimedes' principle · Capillarity · Elastic potential energy · Elastic energy density · Breaking stress · Poisson's ratio · Bulk modulus · Compressibility · Modulus of rigidity · Elastic moduli · Stress-strain curve · Hooke's law · Force constant of a wire · Elastic energy · Thermal stress · Elastic behaviour · Dimensions · Bulk modulus of a gas · Surface energy · Angle of contact · Surface tension and temperature · Surface tension and surface energy · Poiseuille's law · Reynolds number · Viscous force · Viscosity and temperature · Terminal velocity · Stokes' law · Fluid flow

8 free Properties of Solids and Liquids practice questions with answers

Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.

1. Question 1 · medium · Calorimetry and change of state

   Sweating helps cool the human body mainly because:

   • A.sweat is naturally colder than the skin, so it directly lowers skin temperature on contact
   • B.as sweat evaporates from the skin, it absorbs its latent heat of vaporization from the body, carrying that energy away
   • C.sweat has an unusually high boiling point, so it draws heat from the body while staying liquid
   • D.the increased humidity near the skin traps heat away from the body more effectively
   Show answer and explanation

   Answer: B. as sweat evaporates from the skin, it absorbs its latent heat of vaporization from the body, carrying that energy away

   Evaporation requires latent heat; sweat draws this energy from the skin as it turns to vapour, so the skin loses heat and cools down.

   Liquid molecules escaping into vapour must absorb energy equal to the latent heat of vaporization to overcome intermolecular attraction, even at temperatures well below the boiling point (evaporation, unlike boiling, occurs at the liquid's surface at any temperature). This energy is drawn from the surroundings — here, the skin — so the skin cools as sweat evaporates. On humid days, the air is already closer to saturated with water vapour, so evaporation slows, which is why sweating feels less effective at cooling in humid weather (making option D's claim exactly backwards).

   Common mistake: Believing sweat cools by being cold itself, rather than by absorbing latent heat as it evaporates

2. Question 2 · easy · Elasticity

   A wire is loaded gradually. Up to a certain load it regains its original length completely when the load is removed, but beyond that load a small permanent deformation remains even after the load is removed. This load corresponds to the wire's

   • A.elastic limit
   • B.breaking point (fracture load)
   • C.point where strain first becomes proportional to stress
   • D.state of maximum stress the wire can bear before breaking (ultimate tensile strength)
   Show answer and explanation

   Answer: A. elastic limit

   The elastic limit is, by definition, the greatest load up to which a material returns exactly to its original dimensions on unloading. Beyond it, permanent (plastic) deformation sets in.

   As a wire is loaded, it first passes through a region where it obeys Hooke's law and returns fully to its original length when unloaded. The largest stress for which this complete recovery still occurs is called the elastic limit. Loading beyond this point causes some plastic (permanent) strain to remain after the load is removed. The breaking point and ultimate tensile strength both occur later, after substantial plastic flow; the proportional limit marks where linearity begins, which is essentially the start of loading, not the boundary being described here.

   Common mistake: Mixing up elastic limit with breaking point or ultimate tensile strength.

3. Question 3 · medium · Elasticity

   A wire is loaded well beyond its elastic limit and then the load is completely removed. A student claims the wire must return exactly to its original length because "removing the load removes the stress." This claim is

   • A.incorrect — beyond the elastic limit the material undergoes plastic deformation and retains a permanent extension even after the load is removed
   • B.correct — Hooke's law guarantees full recovery for any elastic material regardless of the load applied
   • C.correct, but only for metallic wires and not for polymer strands
   • D.incorrect — the wire actually contracts to less than its original length once unloaded
   Show answer and explanation

   Answer: A. incorrect — beyond the elastic limit the material undergoes plastic deformation and retains a permanent extension even after the load is removed

   Beyond the elastic limit, some strain becomes permanent (plastic). Removing the load removes only the elastic part of the deformation, leaving the wire longer than before.

   Within the elastic limit, a wire's deformation is fully recoverable, and removing the load does bring it back to its original length. But once the applied stress exceeds the elastic limit, part of the strain becomes plastic — the atomic planes have permanently slipped past one another. On unloading, only the elastic component of the strain is recovered; the plastic component remains as a permanent set. So the wire ends up slightly longer than its original length, not restored to it, and certainly not shorter than it.

   Common mistake: Assuming any material always fully recovers on unloading, regardless of how far it was strained.

4. Question 4 · medium · Thermal expansion

   To shrink-fit a steel tyre (rim) onto a wooden cart wheel whose outer diameter is slightly larger than the tyre's inner diameter at room temperature, workers first heat the steel tyre and then slip it over the wheel. This works because heating the tyre:

   • A.increases its thickness, letting it grip the wheel more tightly
   • B.decreases its inner diameter, allowing a snug fit as soon as it is heated
   • C.melts a thin layer of steel that later re-solidifies moulded around the wheel
   • D.increases its inner diameter enough to slip over the wheel; the tyre then shrinks tightly onto the wheel as it cools back down
   Show answer and explanation

   Answer: D. increases its inner diameter enough to slip over the wheel; the tyre then shrinks tightly onto the wheel as it cools back down

   Heating expands the tyre's bore (its inner diameter grows just like a hole in a heated plate), letting it slide over the wheel; cooling afterward shrinks the bore back down onto the wheel, producing a tight, permanent fit.

   A ring or tyre expands uniformly on heating, including its inner diameter — the cavity behaves as if it were filled with the same material. Heating therefore temporarily enlarges the tyre's bore beyond the wheel's outer diameter, so it can be slipped into place. Once positioned, the tyre is allowed to cool; its bore contracts back toward the original (smaller) value, but is now stopped by the wheel underneath, so it clamps down with a strong, uniform compressive grip. This is the standard industrial 'shrink fit' technique, a direct application of thermal expansion of a hole.

   Common mistake: Believing that heating a ring shrinks, rather than enlarges, its inner diameter

5. Question 5 · easy · Fluid dynamics

   In streamline (laminar) flow of a liquid, the velocity of fluid particles passing through a particular fixed point in the flow is

   • A.different every time a new particle passes through that point, even though the overall flow is steady
   • B.the same as the velocity at every other point along the entire streamline
   • C.directed randomly, changing unpredictably from instant to instant at that point
   • D.the same for every particle that passes through it, equal to the fixed velocity associated with that point, though this velocity may differ from point to point along the streamline
   Show answer and explanation

   Answer: D. the same for every particle that passes through it, equal to the fixed velocity associated with that point, though this velocity may differ from point to point along the streamline

   Steady streamline flow means the velocity at each fixed point does not change with time: every particle passing through that point has the same velocity, though different points (of different cross-section) can have different velocities.

   Streamline (laminar) flow is defined as flow in which the velocity at any fixed point in the fluid remains constant in time, so that every fluid particle that passes through that point does so with exactly the same velocity as every particle before it. This does not mean the velocity is the same everywhere along the streamline — by the equation of continuity, speed changes as the cross-sectional area changes. The distinguishing feature of streamline flow is the absence of time variation at a fixed point, not spatial uniformity.

   Common mistake: Confusing 'steady' (unchanging in time at a point) with 'uniform' (unchanging in space along the streamline).

6. Question 6 · medium · Fluid dynamics

   A short stretch of a blood vessel is partially narrowed by a fatty deposit. Blood flows steadily through this narrowed region. Compared with the wider, healthy region just before it, in the narrowed region the blood

   • A.flows slower and at a higher pressure
   • B.flows at the same speed but at a lower pressure
   • C.flows faster and at a lower pressure
   • D.flows faster and at a higher pressure
   Show answer and explanation

   Answer: C. flows faster and at a lower pressure

   Continuity requires higher speed in the narrower vessel; Bernoulli's theorem then requires lower pressure there, since pressure and speed vary oppositely along a horizontal streamline.

   By the equation of continuity, the smaller cross-sectional area at the narrowed (partially blocked) region forces the blood to speed up there to maintain the same volume flow rate. By Bernoulli's theorem, for flow at roughly the same height, a region of higher speed must have lower pressure. So in the narrowed region, blood flows faster and at reduced pressure compared with the healthy region just upstream. (This pressure drop, combined with the increased speed, is part of why narrowed arteries can be clinically significant — the vessel walls may be drawn inward by the reduced local pressure.)

   Common mistake: Assuming pressure rises together with speed in a narrowed vessel, rather than falling.

7. Question 7 · medium · Fluid dynamics

   In steady fluid flow, two streamlines can never cross each other at any ordinary point of the flow. The physical reason for this is that

   • A.the fluid would need to instantaneously change phase at the crossing point
   • B.crossing streamlines are only ever a sign that the flow has become turbulent
   • C.the fluid's density would have to become infinite exactly at the crossing point
   • D.a fluid particle located at the crossing point would need to have two different velocity directions at the same instant, which contradicts the requirement that a steady flow has a single, well-defined velocity at every point
   Show answer and explanation

   Answer: D. a fluid particle located at the crossing point would need to have two different velocity directions at the same instant, which contradicts the requirement that a steady flow has a single, well-defined velocity at every point

   A streamline is, by definition, tangent to the flow velocity at every point along it. If two streamlines crossed, the fluid at that shared point would need two different velocity directions simultaneously — impossible in steady flow, where velocity at each point is single-valued.

   A streamline is defined as a curve whose tangent at every point gives the direction of the fluid velocity there. In steady flow, the velocity (magnitude and direction) at any given point in space is fixed and unique. If two streamlines were to intersect, the fluid particle passing through that shared point would have to be moving in two different directions at once — a contradiction, since velocity at a point must be single-valued for a well-defined steady flow. This is why diagrams of streamline flow always show non-intersecting curves, and it also underlies why the equation of continuity can be applied consistently along a single, unambiguous tube of flow.

   Common mistake: Attributing the non-crossing property of streamlines to turbulence or unrelated physical effects instead of the basic definition of velocity.

8. Question 8 · easy · Fluid statics

   Pascal's law states that a change in pressure applied to an enclosed, incompressible liquid at rest is

   • A.transmitted only along the vertical direction of the applied force
   • B.transmitted undiminished to every point of the liquid and to the walls of the container, acting equally in all directions
   • C.transmitted undiminished only to points at the same depth as the point of application
   • D.reduced in proportion to the distance from the point of application
   Show answer and explanation

   Answer: B. transmitted undiminished to every point of the liquid and to the walls of the container, acting equally in all directions

   Pascal's law: an externally applied pressure change is transmitted equally and undiminished to every part of an enclosed liquid and acts perpendicular to every surface it touches.

   For an incompressible liquid at rest in a closed container, any increase in pressure applied at one point (say, by a piston) is transmitted without loss to every other point in the liquid and to the container walls, and it acts equally in all directions (since a fluid at rest cannot sustain shear). This is the principle behind hydraulic brakes, lifts and presses: pushing a small piston raises the pressure everywhere in the fluid by the same amount, which then acts over a larger piston to produce a larger force. Options A, C and D each introduce a spurious directional or distance dependence that a static, incompressible liquid does not exhibit.

   Common mistake: Believing the transmitted pressure weakens with distance from the piston, like a wave or field.

Questions about Properties of Solids and Liquids for NEET

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Questions are original NEET720 compositions reviewed for correctness, syllabus fit and option quality. Counts update as the bank grows (1,077 active practice questions in this chapter today).