Surface Tension

The maximum area of tension reinforcement in beams shall not exceed:

Water rises to a height of $10 \mathrm{cm}$ in a capillary tube and mercury falls to a depth of $3.5 \mathrm{cm}$ in the same capillary tube. If the density of mercury is $13.6 \mathrm{gm} {\mathrm{cc}}^{-1}$ and its angle of contact is $135°$ and density of water is $1 \mathrm{gm} {\mathrm{cc}}^{-1}$ and its angle of contact is $0°$, then the ratio of surface tensions of the two liquids is $(\cos 135°=0.7)$

Two arms of a U-tube have unequal diameters $d_1=1.0 \mathrm{mm}$ and $d_2=1.0 \mathrm{cm}$. If water (surface tension $7\times {10}^{-2} \mathrm{N}/\mathrm{m}$) is poured into the tube held in the vertical position, find the difference in the level of water in the U-tube. Assume the angle of contact to be zero.

The radii of two soap bubbles are $r_1$ and $r_2$ . In isothermal conditions, two meet together in vacuum. Then the radius of the resultant bubble is given by

A film of water is formed between two straight parallel wires of length $10 \mathrm{cm}$ each separated by $0.5 \mathrm{cm}$. if their separation is increased by $1 \mathrm{mm}$ while still maintaining their parallelism, how much work will have to be done (surface tension of water $= 7.2\times {10}^{-2} \mathrm{N} {\mathrm{m}}^{-1}$)

A drop of mercury of radius 2mm is split into 8 identical droplets. Find the increase in surface energy.( Surface tension of mercury is 0.465 J/m² )

Radius of a soap bubble is increased from $R$ to $2R$  work done in this process in terms of surface tension is

Radius of a soap bubble is increased from $R$ to $2R$ work done in this process in terms of surface tension is

Two small drops of mercury, each of radius R, coalesce to form a single large drop. The ratio of the total surface energies before and after the change is

A liquid film is formed over a frame $ABCD$ as shown in figure. Wire $CD$ can slide without friction. The mass to be hung from $CD$ to keep it in equilibrium is

There is horizontal film of soap solution. On it a thread is placed in the form of a loop. The film is pierced inside the loop and the thread becomes a circular loop of radius $R$. If the surface tension of the loop be $T$ , then what will be the tension in the thread​

A $10 \mathrm{cm}$ long wire is placed horizontally on the surface of water and is gently pulled up with a force of  $2\times {\mathrm{10}}^{-2} \mathrm{N}$ to keep the wire in equilibrium. The surface tension in  $\mathrm{N} {\mathrm{m}}^{-1}$ of water is

A thin metal disc of radius $r$ floats on water surface and bends the surface downwards along the perimeter making an angle $\theta$ with vertical edge of disc. If the disc displaces a weight of water $W$ and surface tension of water is $T$ , then the weight of metal disc is​

A wooden stick $2 \mathrm{m}$ long is floating on the surface of water. The surface tension of water $0.07 \mathrm{N} {\mathrm{m}}^{-1}$. By putting soap solution on one side of the stick, the surface tension is reduced to $0.06 \mathrm{N} {\mathrm{m}}^{-1}$. The net force on the stick will be

The numerical value of surface tension of any liquid in SI unit is $P$and in CGS system of units is $Q$, then$P: Q$ is

A square frame of wire having diagonal $d$ is floating on the surface of liquid of surface tension $T$. The additional force other than its weight, required to pull out the frame from the liquid is

The work done against surface tension forces in blowing a soap bubble of diameter $1 \mathrm{cm}$ is (The surface tension of soap solution is $2.5\times {10}^2\mathrm{N} {\mathrm{m}}^{-1}$)

Why is the force due to surface tension on an edge of length is $F=2Tl$?

The radius of a soap bubble is increased from $1 \mathrm{cm}$ to $4 \mathrm{cm}$. If the surface tension of the soap solution is $0.021{\mathrm{Nm}}^{-1}$, then the work done to increase the radius is

The INCORRECT statement is