Tag: pressure

Questions Related to pressure

A cubical vessel sealed vessel with edge $L$ is placed on a cart, which is moving horizontally with an acceleration `a' as shown iin figure. The cube is filled with an ideal fluid having density $\rho$. Find the gauge pressure at the centre of the cubical vessel.

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

  1. $\dfrac{Ldg}2$

  2. $\dfrac{Ld(g+a)}2$

  3. $\dfrac{Lda}2$

  4. $\dfrac{Ld(g-a)}2$

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Correct Option: B

State whether given statement is True or False
You find your mass to be $42$kg on a weighing machine. Is your mass more or less than $42$kg?

physics 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:

When you weigh your body, an upward buoyant force acts on your body due to the air (a fluid) present around you. As a result, the body gets pushed slightly upwards, causing the weighing machine to show a reading slightly less than the actual value.

State whether true or false:

A sheet of paper falls slower than one that is crumpled into a ball.

physics 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: A
Explanation:

Sheet crumpled into a ball has a small surface area as compared to the similar unfolded sheet. Therefore, unfolded sheet will experience more resistance due to air as compared to the sheet crumpled into a ball, inspite of same force of gravity acting upon them. It is larger resistance of air which slows down the unfolded sheet, and therefore it falls slower as compared to sheet crumpled into a ball.

Barometer was constructed by

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

  1. Vermicelli

  2. Torricelli

  3. Archimedes

  4. Newton

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Correct Option: B
Explanation:

Barometer is a device used to measure atmospheric pressure. It was first constructed by Torricellli in the year 1643.

The Pressure at any point in the liquid is proportional to :

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. The density of liquid.

  2. The depth of point below the surface.

  3. The acceleration due to gravity.

  4. All the above

Show answer
Correct Option: D
Explanation:

Pressure at any point in the liquid $(P)=hdg$
i.e., $P\alpha h$
(depth of point below the surface)
$\alpha d$ (density of liquid)
$\alpha g$ (acceleration due to gravity)

Liquid pressure at a point in a liquid does not depend on the :

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. Density of liquid

  2. Shape of the vessel in which the liquid is kept

  3. Depth of the point from the surface

  4. Acceleration due to gravity

Show answer
Correct Option: B
Explanation:

pressure in a fluid = $\rho gh $ 

so clearly it is independent of the shape of the vessel in which the liquid is kept .
hence option (B) is correct .

Extremely small pollen grains in water are viewed through a microscope. The grains are seen to
move continually and randomly.
What is the reason for this random movement?

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. The grains are moved by randomly moving water molecules

  2. The grains are moved by random convection currents in the water

  3. The grains are moved by random rays of light reflecting off them

  4. The grains are moved by the random motion of their own atoms

Show answer
Correct Option: A
Explanation:

This is due to brownian motion of fluid particles. The pollen get hitted by the water molecules and carried away by them. 

This is reason behind the random motion of pollen grains in water .

A hose shoots water straight up to a height of $2.5m$. The opening end of the hose an area of $0.75\ cm^{2}$. How much water will come out in one minute ?

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. $21.5\ litre$

  2. $25\ litre$

  3. $30\ litre$

  4. $31.5\ litre$

Show answer
Correct Option: A

The deep sea divers wear specially designed suites to protect from

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. different sea organisms

  2. different sea plants

  3. high water pressure

  4. none

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Correct Option: C
Explanation:

To be able to bear very high pressure of liquid in deep sea.

Fill in the blank spaces by choosing the correct words from the options given below.

The hulls of the______are made very strong to withstand huge pressure exerted by the sea water. 

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. $liquids$

  2. $gases$

  3. $submarines$

  4. All of the above

Show answer
Correct Option: C
Explanation:

Submarines.
The hull of Submarines are specially Strengthened to prevent it from collapsing from the high pressure of the water outside while submerged. Roughly every $30$ feet of depth under water adds another atmosphere of inward pressure on the hull.