Mechanical properties of fluids practice · Medium

A large tank is filled with water to a height $H$. A small hole is made at the base of the tank. It takes ${T_1}$ time to decrease the height of water to $\frac{H}{\eta }\left( {\eta > 1} \right):$ and it takes ${T_2}$ time to take out the rest of water. If ${T_1} = {T_2}$, then the value of $\eta$ is

When a sphere falling in a viscous fluid attains a terminal velocity, then

A bubble of air 2 mm in diameter rises in a liquid of viscosity 0.075 SI units and density $1350 \mathrm{~kg} \mathrm{~m}^{-3}.$ The terminal velocity of the bubble is about

Out of air and liquid, which substance is more viscous?

Statement A: A small drop of mercury is spherical but bigger drops are oval in shape
Statement B: Surface tension of liquid decreases with increase in temperature.

In which one of the following cases will the liquid flow in a pipe be most streamlined

A cylindrical vessel of $92 \mathrm{~cm}$ height is kept filled upto the rim. It has four holes $1,2,3$ and 4 which are respectively at heights of $20 \mathrm{~cm}, 30 \mathrm{~cm}, 46 \mathrm{~cm}$ and $80 \mathrm{~cm}$ from the horizontal floor. The water falling at the maximum horizontal distance from the vessel comes from

A wooden block is floating in a water tank. The block is pressed to its bottom. During the process, work done is equal to

When cooking oil is heated in a frying pan, the oil moves around in the pan more easily when it is hot. The main reason for this is that with rise in temperature, there is a decrease in:

A glass plate is partly dipped vertically in the mercury and the angle of contact is measured. If the plate is inclined, then the angle of contact will

A vessel filled with water stands on a table. In its side, the vessel has small orifice arranged at a distance 25 cm from the bottom of the vessel and at a distance 16 cm from the level of water which is kept constant. The horizontal distance from the orifice at which the jet of water fall on the table is

Calculate the approximate change in density of water in a lake at a depth of $400 \mathrm{~m}$ below the surface. The density of water at the surface is $1030 \mathrm{~kg} / \mathrm{m}^3$ and bulk modulus of water is $2 \times 10^9 \mathrm{~N} / \mathrm{m}^2$.

A liquid is stirred. When stirring is stopped, the liquid comes to rest due to-

Assertion: Liquids and gases are largely incompressible and densities are therefore, nearly constant at all pressures for liquid only.
Reason: Liquids exhibit a large variation in densities with pressure but gases do not.

If the water pressure gauge shows the pressure at ground floor to be $270 \mathrm{~k} \mathrm{Pa}$, how high would water rise in the pipes of a building?

$16c{m^3}$Of water flows per sec through a capillary tube of radius a cm and of length $l$ cm when connected to a pressure head of $h$ cm of water. If a tube of the same length and radius $a/2$ cm is connected to the same pressure head, the quantity of water flowing through the tube per second will be

Bernoulli’s principle applies to streamline flow for which Reynold’s number:

An object is floating in a liquid, kept in a container. The container is placed in a lift. Choose the correct option.

A box filled with water has a small hole on its side near the bottom. It is dropped from the top of a tower. As it falls, a camera attached on the side of the box records the shape of the water stream coming out of the hole. The resulting video will show

A block of wood floats in water with (4/5) th of its volume submerged. If the same block just floats in a liquid, the density of the liquid is (in $\mathrm{kgm}^{-3}$ )

Statement A: A piece of ice floats in water. The level of water remains unchanged when the ice melts completely.
Statement B: According to Archimedes' principle, the loss in weight of the body in the liquid is equal to the weight of the liquid displaced by the immersed part of the body.

Six identical small liquid drops are mixed together to form a bigger drop. The terminal velocity of bigger drop if terminal velocity of small drop is 10 m/s, will be

The work done in blowing a soap bubble of surface tension $0.06 \mathrm{Nm}^{-1}$ from $2 \mathrm{~cm}$ radius to $5 \mathrm{~cm}$ radius is

If $F_C$ and $F_A$ denote cohesive and adhesive forces on a liquid molecule near the surface of a solid, then the surface of liquid is concave, when

A tank filled with non-viscous, incompressible, temperature-independent liquid has a hole in its bottom and water is flowing out of it. If the size of the hole is increased, then:

Statement-A: If the angle of contact is equal to $\pi / 2$ then the level of liquid in capillary is same as outside the capillary.
Statement-B: If the angle of contact is less than $\pi / 2$ then the liquid rises in the capillary.

Two mercury drop (each of radius $r)$ merge to form a bigger drop, if T is the surface tension is

A spring balance reads $w_1$ when a ball of mass $m$ is suspended from it. A weighing machine reads $w_2$ when a beaker of liquid is kept on the pan of balance. When the ball is immersed in liquid, the spring balance reads $w_3$ and the weighing machine reads $w_4$. The two balances are now so arranged that the suspended mass is inside the liquid in a beaker. Then,

A small hole is made at the bottom of a hollow sphere. The water enters into it when it is taken to a depth of 40 cm under water. If the surface tension of water is $0.07\,N{m^{ - 1}},$ diameter of the hole is

Assertion: Oil spreads on cold water.
Reason: The surface tension of oil is greater than that of cold water.