Tag: introduction to pressure

Questions Related to introduction to pressure

Liquid rise in a syringe when its piston is pulled up due to 

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

  1. Atmospheric pressure

  2. Inertia of motion

  3. Inertia of rest

  4. Conservation of momentum

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Correct Option: A
Explanation:

When the piston is pulled up, air pressure inside syringe reduces because of increase in volume. While pressure outside syringe is more than that. So, it pushes liquid into syringe.

Based on which of the following does a water pump draw water?

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

  1. Pressure difference

  2. Bernoulli's principle 

  3. Law of Gravity

  4. None of these

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Correct Option: A
Explanation:

Water pump reduses the pressure at one end of the pipe and pressure difference drives the water to come up from well.

What is the relationship between liquid pressure and the depth of a liquid?

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

  1. Directly proportional

  2. Inversely proportional

  3. Linear

  4. None of these

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Correct Option: A
Explanation:

The relationship between liquid pressure and the depth of a liquid:

Pressure at depth 'h' = density of fluid $\times $ acceleration due to gravity 'g' $\times $  depth 'h'.
Pressure is directly proportional to depth. If we triple the depth, we triple the pressure.

The pressure a liquids exerts against the sides and bottom of a container depends on the 

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

  1. atmospheric pressure

  2. surface area

  3. volume of container

  4. density and depth of liquid

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Correct Option: D
Explanation:

$\because p = h\times d\times g$
where, p = pressure, h = depth (height), d = density,  g = acceleration due to gravity = constant.

So, pressure depends on density and depth of liquid.

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

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

  1. $1.85\ g$

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

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

  4. $500\ g\ dyne\ cm^{-2}$

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Correct Option: C
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 $\Delta P = \Delta P _\textrm{oil} + \Delta P _\textrm{water} = 0.85\times 250g + 1\times 250g=462.5g \textrm{ dyne cm}^{-2}$

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

physics fluids pressure in fluids pressure in liquids introduction to pressure

  1. Fortin's barometer

  2. mercury barometer

  3. anaeroid barometer

  4. Torricelli barometer

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Correct Option: B
Explanation:

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

Hence, option B is correct.

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

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. The density of liquid.

  2. The depth of point below the surface.

  3. The acceleration due to gravity.

  4. All the above

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Correct Option: D
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)

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

physics pressure pressure in fluids pressure in liquids introduction to pressure

  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

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Correct Option: B
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 .

Which of the following scientists invented mercury barometer?

physics fluids pressure in fluids pressure in liquids introduction to pressure

  1. Blaise Pascal

  2. Evangelist Torricelli

  3. Robert Brown

  4. Amedeo Avogadro

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Correct Option: B
Explanation:

Mercury Barometer was invented by Evangelist Torricelli in the year 1643. It is a device used to measure atmospheric pressure.

A fluid exerts pressure in all possible directions of a container.

physics fluids pressure in fluids pressure in liquids introduction to pressure

  1. True

  2. False

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Correct Option: A
Explanation:

this is the property of fluid to exert pressure in all directions of a container.

so option (A) is correct