Properties of Bulk Matter

Easy Recall (3)Direct Application (3)Calculation (2)

Effect of Gravity on Pressure

Easy Recall (2)Direct Application (4)Concept Trap (1)Calculation (1)

Elastic Behaviour

Easy Recall (3)Concept Trap (1)Direct Application (3)Calculation (1)

Excess Pressure Curved Surface

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Easy Recall (3)Direct Application (3)Calculation (2)

Fluid Pressure

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Heat Temperature Thermal Expansion

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Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Heat Transfer

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Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Modulus of Rigidity

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Pascal's Law

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Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Specific Heat Calorimetry

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Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Stokes' Law

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Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Stress Strain Hooke's

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Easy Recall (4)Direct Application (2)Calculation (1)Concept Trap (1)

Surface Energy Tension

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Easy Recall (3)Direct Application (3)Calculation (2)

Terminal Velocity

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Easy Recall (2)Concept Trap (2)Direct Application (3)Calculation (1)

Viscosity

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Young's Modulus

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Easy Recall (3)Direct Application (3)Calculation (2)

Past-paper questions from this unit

17 questions from NEET 2020, 2021, 2022, 2023, 2024, 2025, 2026. Answers verified against NTA official keys.

By year in our set: 2020 (2) · 2021 (2) · 2022 (2) · 2023 (3) · 2024 (3) · 2025 (1) · 2026 (4)

Water flows in a streamline motion through a horizontal pipe of circular cross-section. The pressure difference of water between P and Q is 15 Nm⁻². The area of cross-section at P and Q are 40 cm² and 20 cm², respectively. The rate of flow of water through the pipe, in cm³s⁻¹, is : [Take density of water = 1000 kg m⁻³]

NEET 2026

1100

2200

3300

4400

NTA Answer: Option 4(final)

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Lesson: Terminal Velocity

NEET 2026

In the measurement of viscosity of liquids using terminal velocity experiment, spherical balls of same radius but having different densities are used. The variation of the terminal velocity (v) with the ratio of density of spherical ball (σ) to density of the liquid (ρ), is best represented by :

NTA Answer: Option 1(final)

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Lesson: Heat Temperature Thermal Expansion

NEET 2026

The temperature of a metallic sphere of radius R is increased by a small amount ΔT. If the linear coefficient of thermal expansion of the metal is α, the approximate increase in the volume of the sphere is :

12πR³αΔT

23πR³αΔT

34πR³αΔT

46πR³αΔT

NTA Answer: Option 3(final)

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Lesson: Heat Transfer

NEET 2026

Consider that σ_s, k_B, b represent Stefan-Boltzmann constant, Boltzmann constant and Wien's displacement law constant, respectively. The dimension of σ_s k_B⁻¹ b is :

1[L⁻¹T⁻¹K⁻²]

2[L⁻¹K⁻²]

3[L⁻¹T⁻¹K⁻³]

4[L⁻¹T⁻¹K⁻⁴]

NTA Answer: Option 1(final)

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Lesson: Surface Energy Tension

NEET 2025

A balloon is made of a material of surface tension S and its inflation outlet (from where gas is filled in it) has small area A. It is filled with a gas of density ρ and takes a spherical shape of radius R. When the gas is allowed to flow freely out of it, its radius r changes from R to 0 (zero) in time T. If the speed v(r) of gas coming out of the balloon depends on r as rᵃ and T ∝ Sᵅ Aᵝ ρᵞ Rᵟ then

1a = 1/2, α = 1/2, β = −1/2, γ = 1/2, δ = 7/2

2a = 1/2, α = 1/2, β = −1, γ = +1, δ = 3/2

3a = −1/2, α = −1/2, β = −1, γ = −1/2, δ = 5/2

4a = −1/2, α = −1/2, β = −1, γ = 1/2, δ = 7/2

NTA Answer: Option 4(final)

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Lesson: Young's Modulus

NEET 2024Revised key

The maximum elongation of a steel wire of 1 m length if the elastic limit of steel and its Young’s modulus, respectively, are 8 × 10⁸ N m⁻² and 2 × 10¹¹ N m⁻², is:

14 mm

20.4 mm

340 mm

48 mm

NTA Answer: Option 1(revised_final)

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Lesson: Surface Energy Tension

NEET 2024Revised key

A thin flat circular disc of radius 4.5 cm is placed gently over the surface of water. If surface tension of water is 0.07 Nm–1, then the excess force required to take it away from the surface is

119.8 mN

2198 N

31.98 mN

499 N

NTA Answer: Option 1(revised_final)

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Lesson: Young's Modulus

NEET 2024Revised key

A metallic bar of Young’s modulus, 0.5 × 10¹¹ N m⁻² and coefficient of linear thermal expansion 10⁻⁵ °C⁻¹, length 1 m and area of cross-section 10⁻³ m² is heated from 0°C to 100°C without expansion or bending. The compressive force developed in it is :

15 × 10³ N

250 × 10³ N

3100 × 10³ N

42 × 10³ N

NTA Answer: Option 2(revised_final)

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Lesson: Surface Energy Tension

NEET 2023

The amount of energy required to form a soap bubble of radius 2 cm from a soap solution is nearly (surface tension of soap solution = 0.03 N m⁻¹)

15.06 × 10⁻⁴ J

23.01 × 10⁻⁴ J

350.1 × 10⁻⁴ J

430.16 × 10⁻⁴ J

NTA Answer: Option 2(final)

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The venturi-meter works on

NEET 2023

1Bernoulli’s principle

2The principle of parallel axes

3The principle of perpendicular axes

4Huygen’s principle

NTA Answer: Option 1(final)

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Lesson: Stress Strain Hooke's

NEET 2023

Let a wire be suspended from the ceiling (rigid support) and stretched by a weight W attached at its free end. The longitudinal stress at any point of cross-sectional area A of the wire is

1W/A

2W/2A

3Zero

42W/A

NTA Answer: Option 1(final)

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If a soap bubble expands, the pressure inside the bubble

NEET 2022

1Is equal to the atmospheric pressure

2Decreases

3Increases

4Remains the same

NTA Answer: Option 2(final)

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Lesson: Stress Strain Hooke's

NEET 2022

Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The stretching of a spring is determined by the shear modulus of the material of the spring. Reason (R): A coil spring of copper has more tensile strength than a steel spring of same dimensions. In the light of the above statements, choose the most appropriate answer from the options given below

1(A) is false but (R) is true

2Both (A) and (R) are true and (R) is the correct explanation of (A)

3Both (A) and (R) are true and (R) is not the correct explanation of (A)

4(A) is true but (R) is false

NTA Answer: Option 4(final)

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Lesson: Terminal Velocity

NEET 2021

The velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is d/2, then the viscous force acting on the ball will be

12Mg

2Mg/2

3Mg

43/2 Mg

NTA Answer: Option 2(final)

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Lesson: Heat Transfer

NEET 2021

A cup coffee cools from 90°C to 80°C in t minutes, when the room temperature is 20°C. The time taken by a similar cup of coffee to cool from 80°C to 60°C at a room temperature same at 20°C is

1(5/13)t

2(13/10)t

3(13/5)t

4(10/13)t

NTA Answer: Option 3(final)

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Lesson: Capillary Rise

NEET 2020

A capillary tube of radius r is immersed in water and water rises in it to a height h. The mass of the water in the capillary is 5 g. Another capillary tube of radius 2r is immersed in water. The mass of water that will rise in this tube is :

120.0 g

22.5 g

35.0 g

410.0 g

NTA Answer: Option 4(final)

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Lesson: Specific Heat Calorimetry

NEET 2020

The quantities of heat required to raise the temperature of two solid copper spheres of radii r1 and r2 (r1 = 1.5 r2) through 1 K are in the ratio :

15/3

227/8

39/4

43/2

NTA Answer: Option 2(final)

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Exam traps and common mistakes in this unit

Lesson: Bulk Modulus

Trap

Young's vs bulk modulus confusion

Category: Similar Terms

Student uses Y formula when problem is about volumetric compression (use K) or vice versa.

When it triggers

Problem describes longitudinal stretching (use Y), volumetric pressure (use K), or shear (use G).

How to avoid

Y: longitudinal stress/strain. K: volumetric. G: shear. Match modulus to deformation type.

Trap

Soap bubble vs drop excess pressure

Category: Similar Terms

Student uses 2T/r for soap bubble (drop formula). Bubble has 2 surfaces → 4T/r.

When it triggers

Question mentions soap bubble OR liquid drop OR air bubble in liquid.

How to avoid

Drop in air: 1 surface → 2T/r. Soap bubble in air: 2 surfaces → 4T/r. Air bubble in liquid: 1 surface → 2T/r.

Lesson: Bulk Modulus

Mistake

Uses Young's modulus formula for volumetric compression problem (or vice versa).

Root cause: formula misuse

Correction

Y for longitudinal stretch (FL/A·ΔL); K for volumetric compression (-V·dP/dV); G for shear. Match modulus type to deformation type before computing.

Mistake

Uses 2T/r excess-pressure formula for soap bubble. Bubble has 2 surfaces → 4T/r.

Root cause: concept gap

Correction

Drop in air: 1 surface → ΔP = 2T/r. Soap bubble: 2 surfaces (inner + outer) → ΔP = 4T/r. Air bubble inside liquid: 1 surface → 2T/r.

Lesson: Terminal Velocity

Mistake

Treats v_terminal as linear in r instead of r².

Root cause: formula misuse

Correction

v_t ∝ r² (because Stokes drag ∝ r v, gravity ∝ r³ - r³ = r³_diff). Doubling radius quadruples terminal velocity, not doubles.

Formulas in this unit

Lesson: Angle of Contact

Capillary rise/depression

h = \frac{2 T c o s θ}{ρ g r}

Height a liquid rises (or falls) in a capillary tube. cos(theta) > 0: rises (wetting); < 0: depresses.

Symbol	Quantity	SI Unit
h	capillary height	m
T	surface tension	N/m
theta	contact angle	rad
rho	density	kg/m^3
r	tube radius	m

Valid when

Narrow tube (capillary regime)
Constant theta

Bernoulli's equation

P + \frac{1}{2} ρ v^{2} + ρ g h = const

Conservation of energy along a streamline of incompressible non-viscous flow.

Symbol	Quantity	SI Unit
P	pressure	Pa
rho	density	kg/m^3
v	speed	m/s
g	gravity	m/s^2
h	height	m

Valid when

Steady, non-viscous, incompressible flow
Along a single streamline
No work added/removed

Lesson: Bulk Modulus

Bulk modulus

K = - V \frac{d P}{d V}

Resistance of a material to uniform compression. Inverse: compressibility.

Symbol	Quantity	SI Unit
K	bulk modulus	Pa
V	volume	m^3
P	pressure	Pa

Valid when

Isotropic compression
Within elastic regime

Lesson: Change of State Latent Heat

Latent heat

Q = m L

Heat absorbed/released during phase change at constant T. L_fusion or L_vaporisation.

Symbol	Quantity	SI Unit
Q	heat	J
m	mass	kg
L	latent heat	J/kg

Valid when

Phase transition (constant T during)
All mass m undergoes the transition

Excess pressure inside drop/bubble

Δ P_{drop} = \frac{2 T}{r}; Δ P_{bubble} = \frac{4 T}{r}

Excess internal pressure due to surface tension. Bubble has 2 surfaces, hence factor 4.

Symbol	Quantity	SI Unit
Delta_P	excess pressure	Pa
T	surface tension	N/m
r	radius	m

Valid when

Spherical drop or bubble
Constant T (one fluid pair)

Lesson: Fluid Pressure

Pressure in static fluid

P = P_{0} + ρ g h

Pressure at depth h below free surface of fluid of density rho.

Symbol	Quantity	SI Unit
P	total pressure	Pa
P0	atmospheric/surface pressure	Pa
rho	density	kg/m^3
h	depth	m

Valid when

Static fluid (no flow)
Constant g
Constant rho (incompressible)

Lesson: Heat Temperature Thermal Expansion

Thermal expansion (linear/area/volume)

\frac{Δ L}{L} = α Δ T; \frac{Δ A}{A} = 2 α Δ T; \frac{Δ V}{V} = β Δ T

Fractional change in length, area, volume per degree temperature change.

Symbol	Quantity	SI Unit
alpha	linear coefficient	1/K
beta	volume coefficient	1/K
Delta_T	temperature change	K

Valid when

Isotropic material
Modest temperature range (alpha ~ constant)

Lesson: Heat Transfer

Stefan-Boltzmann radiation law

P = σ ε A T^{4}

Radiation power from a body. Black body epsilon=1; net to surroundings P = sigma*epsilon*A*(T^4 - T_s^4).

Symbol	Quantity	SI Unit
sigma	Stefan-Boltzmann = 5.67e-8	W/m^2/K^4
epsilon	emissivity (0-1)	-
A	surface area	m^2
T	absolute temp	K

Valid when

Body in radiative equilibrium
T in kelvins

Lesson: Specific Heat Calorimetry

Specific heat / heat capacity

Q = m c Δ T

Heat required to raise mass m by temperature Delta_T. Specific heat c is material property.

Symbol	Quantity	SI Unit
Q	heat	J
m	mass	kg
c	specific heat	J/kg/K
Delta_T	temp change	K

Valid when

No phase change during heating
c approximately constant in temp range

Lesson: Stokes' Law

Stokes' law (viscous drag on sphere)

F = 6 π η r v

Drag force on a sphere of radius r moving with velocity v through viscous fluid (low Reynolds number).

Symbol	Quantity	SI Unit
F	drag force	N
eta	viscosity	Pa*s
r	sphere radius	m
v	velocity	m/s

Valid when

Smooth, slow flow (low Reynolds number)
Spherical body
Newtonian fluid

Lesson: Terminal Velocity

Terminal velocity of sphere in viscous fluid

v_{t} = \frac{2 r ^{2} g ( ρ _{s} - ρ _{f} )}{9 η}

Constant velocity reached when net force is zero (gravity balanced by buoyancy + viscous drag).

Symbol	Quantity	SI Unit
v_t	terminal velocity	m/s
r	sphere radius	m
rho_s	sphere density	kg/m^3
rho_f	fluid density	kg/m^3
eta	viscosity	Pa*s

Valid when

Steady state (net force zero)
Stokes regime applicable

Lesson: Young's Modulus

Young's modulus

Y = \frac{F L}{A Δ L}

Ratio of longitudinal stress to longitudinal strain in a stretched wire/rod within elastic limit.

Symbol	Quantity	SI Unit
Y	Young's modulus	Pa
F	applied force	N
A	cross-section area	m^2
L	original length	m
Delta_L	extension	m

Valid when

Within elastic limit (Hooke's law region)
Uniform cross-section
Force along length

NEET question patterns in this unit

Apply Bernoulli's equation to flow through pipes of varying cross-section / heights / Venturi-like geometries.

InterpretationMedium

Common distractors

forgets height term

Drops rho*g*h term

equates pressures incorrectly

Picks wrong reference points