Tag: pressure in liquids

Questions Related to pressure in liquids

Calculate the vertical height of a mercury column which exerts a pressure of 81600 Pa. (Density of mercury is $13.6 g cm^{-3}$ and $g=10 ms^{-2})$.

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

  1. 0.2 m

  2. 0.4 m

  3. 0.6 m

  4. 0.8 m

Show answer
Correct Option: C
Explanation:

$Pressure (P)=81600 Pa$
$Density (d)=13.6 g cm^{-3}$
$=13.6\times 1000 kg m^{-3}$
$(\therefore 1 g cm^{-3}=1000 kg m^{-3})$

Acceleration due to gravity $(g)=10 ms^{-2}$
$P=hdg$
$\Rightarrow h=\dfrac {P}{dg}=\dfrac {81600}{13.6\times 1000\times 10}$
$\Rightarrow h=0.6 m$
Therefore, vertical height of mercury column is 0.6 m.

A liquid of density $12 kg m^{-3}$ exerts a pressure of 600 Pa at a point inside a liquid. What is height of liquid column above that point? $[g=10 ms^{-2}]$

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

  1. 4 m

  2. 5 m

  3. 6 m

  4. 7 m

Show answer
Correct Option: B
Explanation:

$Denstiy = 12 kg m^{-3}, Pressure=600 Pa$
$Pressure=hdg$
$\Rightarrow hdg=Pressure\Rightarrow height=\dfrac {P}{dg}$
$=\dfrac {600}{12\times 10}m=5m.$

A metal cube is placed in an empty vessel. When water is filled in the vessel so that  cube is completely immersed in the water, the force on the bottom of the vessel in contact with the cube-

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

  1. Will increase

  2. Will decrease

  3. Will remain the same

  4. Will become zero

Show answer
Correct Option: C

Standing liquid exerts pressure on the bottom due to its:

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

  1. mass

  2. weight

  3. both mass and weight

  4. none of these

Show answer
Correct Option: C
Explanation:

Every liquid has a density and volume which implies that it has mass & all the bodies having under gravity exerts weight.

A tank filled with water is placed in vacuum. The net pressure at point which is $10 m$ below the surface of water will be $(g = 10 m/s^2)$

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

  1. $100 \ kPa$

  2. $10 \ kPa$

  3. $1 \ kPa$

  4. Zero

Show answer
Correct Option: B
A fluid exert pressure 
physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. only downwards

  2. only upwards

  3. in all directions

  4. Fluids do not exert pressure

Show answer
Correct Option: C
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.

Pressure is exerted by fluids because of their weight. Static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity. They exert pressure in all directions, which is given by $F=PA$
where $P$ is the pressure, and $A$ is the area on which force acts.

Which of the following can exert pressure
physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. Solids

  2. Liquids

  3. Gases

  4. All of the above

Show answer
Correct Option: D
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.

Pressure is exerted by fluids because of their weight. Static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity.
Well knowingly, the solids exert pressure on the surface on which they are placed, given by $P=\dfrac{mg}{A}$
Hence correct answer is option D.

Which of the following is true?

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

  1. Fluid do not have any weight

  2. Only liquids have weight

  3. Only gases have weight

  4. Fluids have weight

Show answer
Correct Option: D
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.

Pressure is exerted by fluids because of their weight. Static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity.

Two stretched membranes of area $2 cm^2$ and $3 cm^2$ are placed in a liquid at the same depth. The ratio of the pressure on them is :

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

  1. $1 : 1$

  2. $2 : 3$

  3. $3 : 2$

  4. $2^2 : 3^2$

Show answer
Correct Option: A
Explanation:

pressure depends on depth not on area so the two stretched membrane would  have  equal pressure.

so ratio of their pressures would be 1 : 1.
hence option (A) is correct

Fill in the blank

Fluids at a given depth exert ______ pressure in all directions 

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

  1. same

  2. independent

  3. different

  4. zero

Show answer
Correct Option: A
Explanation:

Fluids at a given depth exert same pressure in all directions.
Pressure of a liquid is directly proportional to the depth, and for a given depth the liquid exerts the same pressure in all directions according to Pascal's law.