Tag: physics

Questions Related to physics

A tank filled with water is placed in vacuum. The net pressure at point which is $10 m$ below the surface of water will be $(g = 10 m/s^2)$

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. $100 \ kPa$

  2. $10 \ kPa$

  3. $1 \ kPa$

  4. Zero

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Correct Option: B
A fluid exert pressure 
physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. only downwards

  2. only upwards

  3. in all directions

  4. Fluids do not exert pressure

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Correct Option: C
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.

Pressure is exerted by fluids because of their weight. Static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity. They exert pressure in all directions, which is given by $F=PA$
where $P$ is the pressure, and $A$ is the area on which force acts.

Which of the following can exert pressure
physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. Solids

  2. Liquids

  3. Gases

  4. All of the above

Show answer
Correct Option: D
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.

Pressure is exerted by fluids because of their weight. Static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity.
Well knowingly, the solids exert pressure on the surface on which they are placed, given by $P=\dfrac{mg}{A}$
Hence correct answer is option D.

Which of the following is true?

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. Fluid do not have any weight

  2. Only liquids have weight

  3. Only gases have weight

  4. Fluids have weight

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Correct Option: D
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.

Pressure is exerted by fluids because of their weight. Static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity.

Two stretched membranes of area $2 cm^2$ and $3 cm^2$ are placed in a liquid at the same depth. The ratio of the pressure on them is :

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. $1 : 1$

  2. $2 : 3$

  3. $3 : 2$

  4. $2^2 : 3^2$

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Correct Option: A
Explanation:

pressure depends on depth not on area so the two stretched membrane would  have  equal pressure.

so ratio of their pressures would be 1 : 1.
hence option (A) is correct

Fill in the blank

Fluids at a given depth exert ______ pressure in all directions 

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. same

  2. independent

  3. different

  4. zero

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Correct Option: A
Explanation:

Fluids at a given depth exert same pressure in all directions.
Pressure of a liquid is directly proportional to the depth, and for a given depth the liquid exerts the same pressure in all directions according to Pascal's law.

The most characteristic property of a liquid is :

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. elasticity

  2. fluidity

  3. formless

  4. volume conservation

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Correct Option: D
Explanation:

a liquid is  substance that flows freely but is of constant volume, having a consistency like that of water or oil.
The most characteristic feature is volume conserrvation.

A block of wood floats separately in river water and then in ocean water. Then the weight of the displaced river water is

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. equal to the weight of the displaced ocean water.

  2. less than the weight of the displaced ocean water.

  3. more than the weight of the displaced ocean water.

  4. not dependent on the density of the wooden block.

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Correct Option: A

The pressure exerted by liquid on container 

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. increases with depth

  2. decreases with depth

  3. remains unchanged with depth

  4. none of the above

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Correct Option: A
Explanation:

$\because p = h\times d\times d$
where, p = pressure
             h = depth
             d = density
so when depth is increases pressure is also increases.

The fluids in a confined space exert pressure in which direction?

physics forces and matter pressure in fluids pressure in liquids introduction to pressure

  1. Upward

  2. Downward

  3. Forward

  4. All directions

Show answer
Correct Option: D
Explanation:

Pascal's law or the principle of transmission of fluid-pressure is a principle in fluid mechanics that states that pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure variations (initial differences) remain the same.

so option ( D) would be correct