Tag: pressure in fluids and atmospheric pressure

Questions Related to pressure in fluids and atmospheric pressure

When the pressure of water is increased, the boiling temperature of water as compared to $100^oC$ will be :

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

  1. lower

  2. the same

  3. higher

  4. on the critical temperature

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Correct Option: C
Explanation:

(C)

The boiling point are the conditions of temperature and pressure, when the vapour pressure of the boiling liquid is EQUAL to the ambient pressure, and bubbles of vapour form directly in the liquid. 
On increasing the pressure water has to be elevated much higher temperature for its pressure to be equal to net applied pressure on it and therefore the water will boil at higher temprature

The foundations of high-rise buildings are kept wide so that they may exert more pressure on the ground.

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

  1. True

  2. False

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Correct Option: B
Explanation:

False. Wide foundations exert lesser pressure because increase in area of contact reduces the pressure and the buildings do not sink.

Which of the following statement is NOT true.

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

  1. A freely falling body is acted upon by gravitational force

  2. pressure on top of mount everest is much more than 1 atm

  3. S.I. unit of pressure is pascal

  4. the blood vessels in our body maintains the internal pressure equal to the atmospheric pressure

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Correct Option: B,D
Explanation:

A free falling object is an object that is falling under the sole influence of gravity.
Atmospheric pressure decreases with height above the surface of a planet because there is less total mass in the atmosphere above a reference point as the height of the reference point increases. The standard atmospheric pressure at sea level is 1 atmosphere.
Pressure is generally measured in units of Pascals and S.I. unit of pressure is pascal.
The normal atmospheric pressure is 760 mm of Hg. But the normal human blood pressure is around 120/80 mm only.
Answer (B) & (D) 
(B) pressure on top of mount everest is much more than 1 atm
(D) the blood vessels in our body maintains the internal pressure equal to the 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

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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 $B$

At sea level, the vertical height of mercury supported in the tube of simple barometer is ______ $cm$ above the mercury level in the bowl.
physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure devices to measure pressure

  1. $36$

  2. $76$

  3. $100$

  4. $7$

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Correct Option: B
Explanation:

The height to which mercury rises in simple barometer is $76cm$.

This is the reason that  atmospheric pressure is often expressed as $76cm$ of Hg at sea level.

Length of glass tube in simple barometer is
physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure devices to measure pressure

  1. $100\,mm$

  2. $1\,cm$

  3. $100\,cm$

  4. $1\,mm$

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Correct Option: C
Explanation:

A mercury barometer has a glass tube, of length approximately 100cm, closed at one end with an open mercury-filled reservoir at the base. 

The vacuum created in simple barometer is known as __________ vacuum
physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure devices to measure pressure

  1. Newton's

  2. Barometric

  3. Torricellian

  4. Archimedes

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Correct Option: C
Explanation:

A simple barometer or a mercury barometer has a glass tube closed at one end with an open mercury-filled reservoir at the base. The weight of the mercury creates a vacuum in the top of the tube known as Torricellian vacuum. 

The liquid used in simple barometer is

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

  1. Glycerine

  2. Kerosene

  3. Mercury

  4. Halogen

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Correct Option: C
Explanation:

A mercury barometer, or a simple barometer, has a glass tube, of length approximately 100cm, closed at one end with an open mercury-filled reservoir at the base. The weight of the mercury creates a vacuum in the top of the tube known as Torricellian vacuum. Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir. High atmospheric pressure places more force on the reservoir, forcing mercury higher in the column. Low pressure allows the mercury to drop to a lower level in the column by lowering the force placed on the reservoir.