Tag: fluid pressure

Questions Related to fluid pressure

Water rises in a vertical capillary tube upto a length of $10cm.$ If the tube is inclined at $45^o$, the length of water risen in the tube will be,

physics fluid pressure pressure exerted by a liquid column pressure at a certain depth in liquid variation of pressure with depth

  1. $10 cm$

  2. $10 \sqrt2 cm$

  3. $\displaystyle \dfrac {10}{\sqrt2}$

  4. none of these

Show answer
Correct Option: B
Explanation:

The vertical rise in the level of liquid is constant.
Hence for an inclined tube, the effective length is $ \displaystyle\dfrac {h}{\cos\theta} $
So, the length of water risen in the tube will be $ 10 \sqrt 2 cm $

If the value of atmospheric pressure is $10^6$ dyne $cm^{-2}$, its value in SI units is

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $10^4 N m^{-2}$

  2. $10^6 N m^{-2}$

  3. $10^5 N m^{-2}$

  4. $10^3 N m^{-2}$

Show answer
Correct Option: C
Explanation:

Pressure = $\displaystyle \frac{F}{A}$ $\because 10^6$ dyne $cm^{-2} = 10^5 N m^{-2}$.

A pressure equivalent of 1 mm is called a

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. bar

  2. torr

  3. pascal

  4. atm

Show answer
Correct Option: B
Explanation:

We have,

              $1atm=760mm$ of Hg$=760torr$,
Hence, one torr is the millimeter of mercury i.e. A pressure equivalent to 1 mm.

$1  atm=Z$  pascal. Then find the value of $Z$?

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. 760

  2. 1000

  3. 101325

  4. 10

Show answer
Correct Option: C
Explanation:

$1atm$ is the standard atmospheric pressure. 

In SI units, the atmospheric pressure is $1atm=1.01325\times 10^{5}Nm^{-2}$
$=101325Pa$

One atmospheric pressure (atm)  is equal to

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. 101325 Pa

  2. 1013.25 Pa

  3. 101.325 Pa

  4. 10.1325 Pa

Show answer
Correct Option: A
Explanation:

One Pascal is the pressure exerted by a force of one newton, normally on an area of one square meter.

Atmospheric pressure is the force per unit area by the weight of air on a point.
One atmospheric pressure is related with the Pascal as:
    $1atm=101325Pa$

State the S.I. unit. of pressure

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. Newton

  2. Pascal

  3. Coulomb

  4. Copernicus

Show answer
Correct Option: B
Explanation:

Pressure is defined as force per unit area. It is usually more convenient to use pressure rather than force to describe the influences upon fluid behavior. The standard unit for pressure is the Pascal, which is a Newton per square meter.

$1Pa=1Nm^{-2}$

1 atm is

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. 780 torr

  2. 760 torr

  3. 750 torr

  4. 790 torr

Show answer
Correct Option: B
Explanation:

Both $atm$ and $torr$ is the unit of pressure.

$1atm$ is the atmospheric pressure=$1.01\times 10^5Pa$
Torr is expressed as $1 torr=\dfrac{1atm}{760}$

1 torr is equal to 

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. 196 Pa

  2. 133 Pa

  3. 101 Pa

  4. 120 Pa

Show answer
Correct Option: B
Explanation:

We have:

               $1 atm=760 torr$ ,
and         $1atm=101325Pa$ ,
hence,    $760torr=101325Pa$ 
or             $1torr=101325/760=133.3Pa$

Which of the following is/are the example(s) of absolute pressure 

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. deep vacuum pressure

  2. altimeter pressure

  3. blood pressure

  4. both (A) & (B)

Show answer
Correct Option: D
Explanation:

Absolute pressure: It uses absolute zero (pressure in vacuum) as its zero point.

Gauge pressure: It uses atmospheric pressure  as its zero point.
Therefore, Absolute pressure = Atmospheric pressure + Gauge pressure 
Blood pressure is an example of gauge pressure .
Deep vacuum pressure and altimeter pressure are examples of absolute pressure.

The correct relationship between gauge pressure, atmospheric pressure and absolute pressure is 

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. Gauge pressure = Atmospheric pressure - Absolute pressure

  2. Gauge pressure = Atmospheric pressure + Absolute pressure

  3. Absolute pressure = Atmospheric pressure + Gauge pressure

  4. None of the above

Show answer
Correct Option: C
Explanation:

Absolute pressure: It uses absolute zero (pressure in vacuum) as its zero point.

Gauge pressure: It uses atmospheric pressure  as its zero point.
Therefore, Absolute pressure = Atmospheric pressure + Gauge pressure