W is the work done in forming a bubble of radius r, the work is done in forming a bubble of radius 2r will be:-
NEET Practice Questions (MCQs) with Answers & Solutions
Practice free NEET NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
Equation of continuity based on :
It is based on the conservation of mass
Bernoulli's theorem is based on :
Conceptual
Two spherical soap bubbles of radii r1 and r2 in vaccum collapse under isothermal condition. The resulting bubble has radius equal to :
The energy needed in breaking of a drop of liquid of radius R into n drops of radius r is given by (T is surface tension and P is atmospheric pressure) :
A rectangular film of liquid is extended from (4 cm) to . If the work done is J,the value of the surface tension of the liquid is
(b) Increases in surface energy= work done in areaSurface tension
Increase in surface area,
=
So, work done, W=T.
Three liquids of densities (with ), having the same value of surface tension T, rise to the same height in three identical capillaries. The angles of contact obey
(b) According to ascent formula for capillary tube,
Two non-mixing liquids of densities and n(n>1) are put in a container. The height of each liquid is h. A solid cylinder floats with its axis vertical and length pL in the denser liquid. The density of the cylinder is d. The cylinder floats with its axis vertical and length pL (p<1) in the denser liquid. The density d is equal to
According to Archimedes' principle, the buoyant force on the cylinder is equal to the weight of the liquid displaced by the cylinder. The volume of the liquid displaced is pLÏ€r^2, where r is the radius of the cylinder. The weight of this liquid is pLÏ€r^2Ïn. This weight must equal the weight of the cylinder, which is pLÏ€r^2d. Therefore, d = Ïn.
The approximate depth of an ocean is 2700 m. The compressibility of water is 45.4 x 10-11 Pa-1 and density of water is 103kg/m3. What fractional compression of water will be obtained at the bottom of the ocean?
Given d=2700 m
ρ=103kg/m3
Compressibility=45.4 x 10-11 Pa-1 per pascal
The pressure at the bottom of ocean is given by
P=ρgd=103x10x2700=27x106Pa
So, fractional compression=compressibility x pressure
=45.4 x 10-11x 27 x106
=1.2x10-2
A wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250 m2. Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be (Pair=1.2kg/m3)
From Bernoulli's theorem
p1+ρv12=p2+ρv22
where, p1 and p2 are pressure inside and outside the roof and v1 v2 are velocities of wind inside and outside the roof, Neglect the width of the roof.
Pressure difference is
p1-p2=ρ(v22-v12)
=x1.2(402-0)=960N/m2
Force acting on the roof is given by
F=(p1-p2)A=960 x 250=24x104N=24X105N
As the pressure inside the roof is more than outside to it. So the force will act m the upward direction, i.e. F=24x105N,upward
Ready to ace NEET?
Free access · No credit card required
Frequently Asked Questions
Yes. You can attempt every NEET question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.
No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.
The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.