Tag: pressure in air

Questions Related to pressure in air

While filling a syringe with liquid which of the following is true for pressure inside the barrel and the atmospheric pressure acting on the liquid?

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

  1. pressure inside the barrel is less than atmospheric pressure

  2. pressure inside the barrel is more than atmospheric pressure

  3. pressure inside the barrel is same as atmospheric pressure

  4. none of these

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Correct Option: A
Explanation:

When the plunger is pulled up in the barrel, the pressure inside the barrel is much less than atmospheric pressure. As a result atmospheric pressure forces the liquid to rise up in the syringe.

Air pressure at sea level is ________ of mercury.
physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $6\,m$

  2. $0.36\,km$

  3. $60\,cm$

  4. $0.76\,m$

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Correct Option: D
Explanation:

When air pressure is measure at the sea level using a mercury barometer, the height upto which the mercury column rises is $76cm$.

Hence the atmospheric pressure at this level is also called $0.76m$ of mercury.

Which of the following are the common consequences of atmospheric pressure in our daily life.

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

  1. Sucking a drink with a straw

  2. Filling a syringe with a liquid

  3. Filling ink in a fountain pen

  4. All of the above

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Correct Option: D
Explanation:

Liquid flows from higher pressure region to the lower pressure region.

Thus sucking a drink with a straw, filling a syringe with a liquid and filling ink in a fountain pen are the consequences of atmospheric pressure.

Atmospheric pressure exerted on earth is due to the.

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

  1. Gravitational pull

  2. Revolution of earth

  3. Rotation of earth

  4. Uneven heating of earth

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Correct Option: A
Explanation:

The atmospheric pressure exerted on earth is due to gravitational pull of the earth and is about 14.7 psi.

Hence, option A is correct.

A boiler is made of a copper plate 2.4mm thick with an inside coating of a 0.2mm thick layer of tin.The surface area exposed to gases at ${\rm{70}}{{\rm{0}}^{\rm{0}}}{\rm{C is 400c}}{{\rm{m}}^{\rm{2}}}$ . The amount of steam that could be generated per hour at atmospheric pressure is  ${\rm{(}}{{\rm{K}} _{{\rm{cu}}}}{\rm{ = 0}}{\rm{.9 and }}{{\rm{K}} _{{\rm{tin}}}}{\rm{ = 0}}{\rm{.15cal/cm/s}}{{\rm{/}}^{\rm{0}}}{\rm{C and }}{{\rm{L}} _{{\rm{steam}}}}{\rm{ = 540cal/g)}}$

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

  1. 5000kg

  2. 1000kg

  3. 4000kg

  4. 200kg

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Correct Option: C

Icc of water at $ 100^o C $ is given 540 cal of heat and the steam formed accupies 167 Icc at the atmospheric pressure. Then workdone against atmospheric pressure in this process is nearly.

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

  1. 540 cal

  2. 500 cal

  3. 40 cal

  4. 100 cal

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Correct Option: C

A partially inflated balloon expands fully when 

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

  1. It is put into warm water

  2. It is put into cold water

  3. It is into water at room temperature

  4. None of the above

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Correct Option: D

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

Show answer
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