Question 1 :
Two separate air bubble (radii 0.002 m and 0.004 m) formed of the same liquid (surface tension 0.07 $Nm^{-1}$)come together to form a double bubble. The radius and the sense of curvature of internal film surface, common to both the bubbles is:
Question 2 :
The unit of the coefficient of viscosity in S.I. system is:<br/>
Question 3 :
The work done in blowing a soap bubble of radius $r$ of the solution of surface tension $T$ will be<br/>
Question 4 :
Assertion: Dust particles generally settle down in a closed room.
Reason: The terminal velocity is inversely proportional to the square of their radii.
Question 6 :
Two spheres of the same material, but of radii R and 3R are allowed to fall vertically downwards through a liquid of density $\sigma$. The ratio of their terminal velocities is
Question 7 :
If the diameter of a soap bubble is 20 mm and if the surface tension of soap water is 0.04N.m$^{-1}$, the excess pressure inside the bubble is in Nm$^{-2}$ is :<br/>
Question 10 :
When a drop of water is dropped on oil surface, then :
Question 13 :
Two soap bubbles each of radius r are touching each other. The radius of curvature of the common surface will be :-
Question 14 :
The terminal velocity $V$ of a spherical ball of lead of radius $R$ falling through a viscous liquid varies with $R$ such that:
Question 15 :
If air is blown through the space between a calendar suspended from a nail on wall and the wall, then:
Question 16 :
If the system is not in free fall, which of the following statements is true about hydrostatic pressure?
Question 17 :
The principle of fluid pressure that is used in hydraulic brakes or lifts is that.<br>
Question 19 :
Eight drops of equal size are falling through air with steady velocity of 10 cm/sec. If the drops coalesce, what could be its terminal velocity?
Question 21 :
Assertion: Falling raindrops acquire a terminal velocity.
Reason: A constant force in the direction of motion and a velocity dependent force opposite to the direction of motion, never results in the acquisition of terminal velocity.
Question 22 :
<br>In the hydraulic braking system , the piston in the master cylinder is connected by mechanical linkage to the
Question 23 :
Water is flowing through a very narrow tube. The velocity of water below which the flow remains a streamline flow is known as:
Question 25 :
If the meniscus of a liquid is concave in shape, then
Question 28 :
A car moving on a road when overtaken by a bus:
Question 29 :
What is ratio of surface energy of $1$ small drop and $1$ large drop, if $1000$ small drops combined to form $1$ large drop<br>
Question 31 :
When a sphere falling in a viscous fluid attains a terminal velocity, then:
Question 32 :
In a laminar flow the velocity of the liquid in contact with the walls of the tube is
Question 33 :
After terminal velocity is reached the acceleration of a body falling through a viscous fluid is :
Question 34 :
An iron sphere of mass $20\times 10^{-3} kg$ falls through a viscous liquid with terminal velocity $0.5ms^{-1}$.The terminal velocity (in $ms^{-1}$) of another iron sphere of mass $54 \times 10^{-2}kg$ is:
Question 35 :
A small hollow sphere, which has a small hole in it, is immersed in water to a depth of 0.5 m before any drop penetrates into it. If surface tension for water is 0.073 N/m, the radius of the hole is :[Assume pressure inside the sphere to be atmospheric pressure]
Question 36 :
If an air bubble of the same dimensions were formed at a depth of 30 cm inside a container containing the soap solution of relative density 1.20, then the pressure inside the bubble is (Take 1 atm = $1.01 \times 10^5$ Pa)
Question 37 :
A soap bubble of radius $1.0\ cm$ is formed inside another soap bubble of radius $2.0\ cm$. The radius of an another soap bubble which has the same pressure difference as that between the inside of the smaller and outside of large soap bubble, in meters is
Question 38 :
A steel ball of mass 'm' falls in a viscous liquid with a terminal velocity $4 ms^{-1}$ . If another steel ball of mass 8m falls through the same liquid then its terminal velocity is <br>
Question 39 :
If two soap bubbles of different radii are connected by a tube, then :
Question 41 :
Assertion: An object from a greater height reaches a steady terminal velocity.
Reason: The viscous forces on a body depends upon its velocity. The greater the velocity the greater is the viscous force.
Question 42 :
A soap bubble of radius $r$ is blown upto form a bubble of radius $2r$ under isothermal conditions. If $\pi \sigma$ is the surface tension of soap solution, the energy spent in doing so is
Question 43 :
The method of concentration of the ore that makes use of difference in density between ore and impurities is called __________.
