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Multiple choice physics forces and matter pressure in fluids pressure in liquids introduction to pressure

A tank $5\ m$ high is half filled with water and then is filled to the top with oil of density $0.85\ g\ cm^{-3}$. The pressure at the bottom of the tank, due to these liquids, is

  1. $1.85\ g$

  2. $89.25\ g\ dyne\ cm^{-3}$

  3. $462.5\ g\ dyne\ cm^{-2}$

  4. $500\ g\ dyne\ cm^{-2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We know that the pressure increases as we go deep into a liquid. The relation is given by $\Delta P = \rho g\Delta h$


Given that the tank is half filled with water and half with oil.
Thus, $h _\textrm{oil} = 2.5\textrm{ m}$ and $h _\textrm{water} = 2.5\textrm{ m}$

Thus, pressure at the bottom of the tank is $\Delta P = \Delta P _\textrm{oil} + \Delta P _\textrm{water} = 0.85\times 250g + 1\times 250g=462.5g \textrm{ dyne cm}^{-2}$

Multiple choice physics fluids pressure in fluids pressure in liquids introduction to pressure

A barometer which measures atmospheric pressure more accurately is ..........

  1. Fortin's barometer

  2. mercury barometer

  3. anaeroid barometer

  4. Torricelli barometer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A barometer which measures atmospheric pressure most accurately is mercury barometer.

Hence, option B is correct.

Multiple choice physics pressure pressure in fluids pressure in liquids introduction to pressure

The Pressure at any point in the liquid is proportional to :

  1. The density of liquid.

  2. The depth of point below the surface.

  3. The acceleration due to gravity.

  4. All the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Pressure at any point in the liquid $(P)=hdg$
i.e., $P\alpha h$
(depth of point below the surface)
$\alpha d$ (density of liquid)
$\alpha g$ (acceleration due to gravity)

Multiple choice physics pressure pressure in fluids pressure in liquids introduction to pressure

Liquid pressure at a point in a liquid does not depend on the :

  1. Density of liquid

  2. Shape of the vessel in which the liquid is kept

  3. Depth of the point from the surface

  4. Acceleration due to gravity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

pressure in a fluid = $\rho gh $ 

so clearly it is independent of the shape of the vessel in which the liquid is kept .
hence option (B) is correct .

Multiple choice physics fluids pressure in fluids pressure in liquids introduction to pressure

Pressure at a point inside the liquid does not depend upon :

  1. The depth of the point below the surface of the liquid.

  2. The nature of the liquid.

  3. The acceleration due to gravity at that point.

  4. The shape of the container.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Pressure at a point inside the liquid $(P)=hdg$
Hence, it depends on the depth of the point below the surface of the liquid the acceleration due to gravity at that point and on the nature of the liquid but not on the shape of the containing liquid.

Multiple choice physics pressure pressure in fluids pressure in liquids introduction to pressure

Extremely small pollen grains in water are viewed through a microscope. The grains are seen to
move continually and randomly.
What is the reason for this random movement?

  1. The grains are moved by randomly moving water molecules

  2. The grains are moved by random convection currents in the water

  3. The grains are moved by random rays of light reflecting off them

  4. The grains are moved by the random motion of their own atoms
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is due to brownian motion of fluid particles. The pollen get hitted by the water molecules and carried away by them. 

This is reason behind the random motion of pollen grains in water .