A thin flat circular disc of radius $$4.5~\text {cm}$$ is placed gently over the surface of water. If surface tension of water is $$0.07~\text{Nm}^{-1},$$ then the excess force required to take it away from the surface is:
1. $$198~\text{N}$$
2. $$1.98~\text{mN}$$
3. $$99~\text{N}$$
4. $$19.8~\text{mN}$$
Subtopic:  Surface Tension |
From NCERT
NEET - 2024
Hints

A wire of length $$L$$ and radius $$r(r<<L)$$ is kept floating on the surface of a liquid of density $$\rho$$. The maximum radius of the wire for which it may not sink is (Surface tension of liquid is $$T$$):
1. $$\sqrt { \dfrac{T}{\rho g}}$$
2. $$\sqrt { \dfrac{2T}{\rho g}}$$
3. $$\sqrt{\dfrac{2T\rho}{\pi g}}$$
4. $$\sqrt{\dfrac{2T} {\pi \rho g}}$$
Subtopic:  Surface Tension |
52%
From NCERT
NEET - 2024
Hints

The pressure experienced by a swimmer $$20~\text{m}$$ below the water surface in a lake is appropriately
[Given density of water = $$10^3 ~\text{kgm}^{-3},~ g=10 ~\text{ms}^{-2}$$ and $$1~\text{atm} = 10^5~\text{Pa}$$]:
 1 $$1~\text{atm}$$ 2 $$2~\text{atm}$$ 3 $$3~\text{atm}$$ 4 $$4~\text{atm}$$
Subtopic:  Pressure |
63%
From NCERT
NEET - 2024
Hints

An ideal fluid is flowing in a non-uniform cross-sectional tube $$XY$$ (as shown in the figure) from end $$X$$ to end $$Y.$$ If $$K_1$$ and $$K_2$$ are the kinetic energy per unit volume of the fluid at $$X$$ and $$Y$$ respectively, then the correct option is:

1. $$K_1\text=K_2$$
2. $${2K}_1\text={K}_2$$
3. $${K}_1>{K}_2$$
4. $${K}_1<{K}_2$$
Subtopic:  Bernoulli's Theorem |
59%
From NCERT
NEET - 2024
Hints

The venturi-meter works on:
 1 The principle of perpendicular axes 2 Huygen's principle 3 Bernoulli's principle 4 The principle of parallel axes
Subtopic:  Bernoulli's Theorem |
82%
From NCERT
NEET - 2023
Hints

The amount of energy required to form a soap bubble of radius $$2~\text{cm}$$ from a soap solution is nearly:
$$($$surface tension of soap solution $$0.03~\text{Nm}^{-1})$$
1. $$50.1 \times 10^{-4}~\text{J}$$
2. $$30.16 \times 10^{-4}~ \text{J}$$
3. $$5.06 \times 10^{-4} ~\text{J}$$
4. $$3.01\times 10^{-4} ~\text{J}$$
Subtopic:  Surface Tension |
58%
From NCERT
NEET - 2023
Hints

Which of the following statements is not true?
 1 The coefficient of viscosity is a scalar quantity. 2 Surface tension is a scalar quantity. 3 Pressure is a vector quantity. 4 Relative density is a scalar quantity.
Subtopic:  Pressure |
68%
From NCERT
NEET - 2023
Hints

The viscous drag acting on a metal sphere of diameter $$1$$ mm, falling through a fluid of viscosity $$0.8$$ Pa-s with a velocity of $$2$$ ms–1 is nearly equal to:
1. $$15\times 10^{-3}~\text{N}$$
2. $$30\times 10^{-3}~\text{N}$$
3. $$1.5\times 10^{-3}~\text{N}$$
4. $$20\times 10^{-3}~\text{N}$$
Subtopic:  Stokes' Law |
59%
From NCERT
NEET - 2023
Hints

If a soap bubble expands, the pressure inside the bubble:
1. is equal to the atmospheric pressure
2. decreases
3. increases
4. remains the same
Subtopic:  Surface Tension |
68%
From NCERT
NEET - 2022
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
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NEET 2025 - Target Batch

A spherical ball is dropped in a long column of a highly viscous liquid. The curve in the graph shown, which represents the speed of the ball ($$v$$) as a function of time ($$t$$) is:

1. $$D$$
2. $$A$$
3. $$B$$
4. $$C$$
Subtopic:  Viscosity |
71%
From NCERT
NEET - 2022
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch