Tag: physics

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Questions Related to physics

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

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:

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
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 $B$

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

One atmospheric pressure (atm)  is equal to

  1. 101325 Pa

  2. 1013.25 Pa

  3. 101.325 Pa

  4. 10.1325 Pa
Reveal answer Fill a bubble to check yourself
A Correct answer
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:
    $1atm=101325Pa$

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

State the S.I. unit. of pressure

  1. Newton

  2. Pascal

  3. Coulomb

  4. Copernicus
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

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

  1. deep vacuum pressure

  2. altimeter pressure

  3. blood pressure

  4. both (A) & (B)
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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