Tag: introduction to atmospheric pressure

Questions Related to introduction to atmospheric pressure

You are riding on your bicycle with inflated tyres. Your friend asks for a lift and sits on the carrier behind you

physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. The air pressure in the tyres increases

  2. The air pressure in the tyres decreases

  3. The air pressure in the tyres remains the same

  4. Nothing inthe system changes except the reaction of the ground

  5. Answer Required

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Correct Option: D
Explanation:

nothing in the system changes except the reaction of the ground.

because the friend will exert its weight on the ground and the ground will exert normal reaction to balance it.

A glass bulb is balanced by a brass weight in a sensitive beam balance. Now the balance is covered by a glass-jar which is then evacuated. Then:

physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. the beam will remain horizontal

  2. the pan containing the bulb will go down

  3. the pan containing the bulb will go

  4. none of the above

Show answer
Correct Option: B
Explanation:

Given, That a glass bulb is balanced by a brass weight in a sensitive beam balance,

Now the balance is covered by a glass jar which is then evacuated.
By evacuating, there will be no air in the glass jar. so the glass bulb will be higher in mass because it contains air inside the glass bulb,
So the pan containing the bulb will go down
Therefore the correct option is $B$

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

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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

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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

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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.