The pressure of air in a soap bubble of $0.7 \ cm$ diameter is $8 \ mm$ of water above the pressure outside. The surface tension of the soap solution is ........ $dyne/cm$.

If two soap bubbles of different radii are connected by a tube,then

Two soap bubbles of radii $R$ and $r$ come in contact. $R$ is more than $r$. The radius of curvature of the common surface is

Air is pushed into a soap bubble to increase its radius from $R$ to $2R$. In this case, the pressure inside the bubble

Two spherical soap bubbles formed in vacuum have diameters $3.0 \, mm$ and $4.0 \, mm$. They coalesce to form a single spherical bubble. If the temperature remains unchanged,find the diameter of the bubble so formed in $mm$.

$A$ cylinder with a movable piston contains air under a pressure $p_1$ and a soap bubble of radius $r$. The pressure $p_2$ to which the air should be compressed by slowly pushing the piston into the cylinder for the soap bubble to reduce its size by half will be: (The surface tension is $\sigma$, and the temperature $T$ is maintained constant)