NEET Physics Mechanical Properties Of Fluids Force Due To Surface Tension MCQs

A thin rectangular plate of dimensions $5 \, cm imes 2 \, cm$ is suspended vertically with its long side horizontal, with half of it immersed in a liquid of surface tension $0.04 \, N/m$. The apparent weight of the plate in the liquid is $0.01 \, N$ less than its weight in air. The contact angle between the liquid and the plate is (Assume $g = 10 \, m/s^2$):

Two soap bubbles of radii $r_1$ and $r_2$ coalesce under isothermal conditions to form a bigger bubble of radius $R$. If the atmospheric pressure is $P_0$, the surface tension of the soap solution is:

A capillary tube of radius $r$ is immersed vertically in a liquid of density $\rho$ and surface tension $T$. The angle of contact is $heta$. The height $h$ to which the liquid rises in the tube is given by:

A small air bubble of radius $r$ rises steadily through a liquid of density $\rho$ at a terminal velocity $v$. If the coefficient of viscosity of the liquid is $\eta$, the surface tension of the liquid is (neglecting the density of air):

A liquid rises to a height 'h' in a capillary tube of radius 'r'. If the radius of the capillary tube is doubled, the height to which the liquid rises in the tube will be:

Two spherical bubbles of radii $r_1$ and $r_2$ in air combine to form a bigger bubble. The radius of the bigger bubble is:

A thin rectangular frame of wire is dipped vertically into water. When it is raised, a thin film of water is formed inside the frame. The force required to raise the frame against the surface tension of water (assuming negligible weight of the frame) is:

Two soap bubbles of radii $r_1$ and $r_2$ coalesce to form a single bubble of radius $R$ under isothermal conditions. If $P$ is the external pressure, then which of the following relations is correct?

A small metal ring of radius 'r' is kept on a large soap bubble of radius 'R' ($r << R$). If the surface tension of the soap solution is 'T', the force pulling the ring towards the center of the bubble is:

The excess pressure inside a soap bubble of radius $R$ is $P$. The excess pressure inside another soap bubble of radius $2R$ will be: