Pressure MCQ Quiz - Objective Question with Answer for Pressure - Download Free PDF

The Correct answer is decrease.

Key Points

• Pressure is defined as the force per unit area. Mathematically, it is expressed as P = F/A, where P is pressure, F is the thrust or force applied, and A is the area of contact.
• If the thrust (F) is kept constant and the area of contact (A) increases, the pressure (P) will decrease as per the inverse relationship.
• This principle is based on the fact that spreading the same force over a larger area results in reduced intensity of pressure at any given point.
• An example can be seen in snowshoes, which are designed to distribute the weight of a person over a larger area to prevent sinking into the snow.
• In practical applications, this concept is used in various fields such as engineering, construction, and material design to ensure proper load distribution and safety.
• Thus, when the area of contact increases while maintaining a constant thrust, the pressure will decrease.

 Additional Information

• Increase
  • If the thrust increases while keeping the area of contact constant, the pressure will increase. This is the opposite scenario.
  • Applications of this principle include tools and machinery like nails, knives, and hydraulic presses, where smaller contact areas increase pressure to perform cutting or piercing tasks.
• Remain the same
  • Pressure remains constant only if both the thrust and the area of contact are unchanged.
  • This is not applicable in the current scenario since the area of contact is increasing.
• First increase, then decrease
  • Such behavior is not observed in the relationship between pressure, thrust, and area.
  • This option does not align with the formula P = F/A.

The Correct answer is Equal to its weight.

Explanation:

• The buoyant force acting on an object is equal to the weight of the fluid displaced by the object. In this case, the object is floating, so the buoyant force is equal to the weight of the object.
• The buoyant force is caused by the pressure difference between the top and bottom of the object. The pressure is greater at the bottom of the object because the fluid is denser at the bottom. This pressure difference creates a force that pushes the object upward.
• When the buoyant force is greater than the weight of the object, the object floats. If the buoyant force is less than the weight of the object, the object will sink. If the buoyant force is equal to the weight of the object, the object will rise to the surface of the liquid.

So, the buoyant force acting on an object that floats in a liquid with half of its volume submerged in the liquid is equal to its weight.

Important Points

• When the buoyant force of liquid is less than the weight of the object, the object will be submerged or sank.
• When the buoyant force of the liquid is greater than the weight of the object, the object will float on the surface of the liquid. 
• NOTES: Buoyancy is the tendency of a liquid to exert an upward force on an object immersed in it.
• The buoyancy of a liquid depends upon the density of the fluid and the volume of the object immersed in the liquid.
• Thus we can say the buoyant force is greater if the volume of an object submerged in a liquid is Larger.

The correct answer is 2 N.

Key Points

• The buoyant force is calculated using Archimedes' principle: Buoyant force = ρ × V × g, where ρ is the density of the fluid, V is the volume of the object submerged, and g is the acceleration due to gravity.
• Given: Density of water (ρ) = 1000 kg/m³, Volume of sphere (V) = 2 × 10⁻⁴ m³, and g = 10 m/s².
• Using the formula: Buoyant force = (1000) × (2 × 10⁻⁴) × (10) = 2 N.
• The buoyant force is independent of the mass of the sphere; it only depends on the displaced fluid's volume and density.
• Therefore, the correct buoyant force exerted by water on the sphere is 2 N.

Additional Information

• Archimedes' Principle:
  • It states that a body immersed in a fluid experiences an upward force equal to the weight of the fluid displaced by it.
  • This principle is fundamental in calculating buoyant forces acting on submerged objects.
• Buoyant Force:
  • The upward force exerted by a fluid on an object submerged in it.
  • It depends on the fluid's density, the object's submerged volume, and gravitational acceleration.
• Density of Water:
  • The standard density of water at room temperature is approximately 1000 kg/m³.
  • It is one of the key parameters used in buoyancy calculations.
• Relation to Gravitational Force:
  • Gravitational acceleration (g) impacts both the object's weight and the buoyant force exerted by the fluid.
  • In standard conditions on Earth, g = 9.8 m/s² (rounded to 10 m/s² for simplicity in calculations).

The correct answer is greater than its weight.​

Key Points

• A body floats in a liquid when the buoyant force exerted by the liquid equals the weight of the body or is greater than its weight.
• The principle governing this phenomenon is Archimedes' Principle, which states that an object submerged in a fluid experiences an upward force equal to the weight of the fluid displaced.
• If the buoyant force is equal to the weight, the body achieves neutral buoyancy and floats partially submerged.
• The body sinks if its weight is greater than the buoyant force, and it rises to the surface if the buoyant force is greater than its weight.
• This balance between weight and buoyant force is essential for objects like ships and submarines to float efficiently on water.

Additional Information

• Buoyant Force:
  • The upward force exerted by a fluid on an object placed in it, counteracting the weight of the object.
  • This force is responsible for making objects float or feel lighter when submerged in liquids.
• Archimedes' Principle:
  • Discovered by the ancient Greek mathematician Archimedes.
  • It states: "The upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid displaced by the body."
• Density and Floating:
  • An object floats if its density is less than the density of the liquid.
  • If the densities are equal, the object remains submerged without sinking or floating (neutral buoyancy).
• Applications of Buoyancy:
  • Shipbuilding: Ships are designed to displace water equal to their weight to float.
  • Submarines: Adjust buoyancy using ballast tanks to sink or float.
  • Hot air balloons: Use buoyancy in air to rise by heating air inside the balloon, reducing its density.

The correct answer is Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.

Key Points

• Pressure is defined as the force applied per unit area, mathematically expressed as Pressure = Force/Area.
• The assertion correctly states that pressure is inversely proportional to the area on which a force is applied. As the area decreases, pressure increases and vice versa.
• The reason explains the relationship effectively: a smaller area concentrates the force over a smaller surface, leading to higher pressure.
• This principle is applied in real-life scenarios, such as sharp objects (e.g., knives or needles) exerting high pressure due to their small contact area.
• Both the assertion and reason align with fundamental concepts in physics, making the reason a valid explanation for the assertion.

Additional Information

• Pressure: A scalar quantity measured in Pascal (Pa), where 1 Pascal = 1 N/m².
• Force: A vector quantity responsible for causing motion or deformation in an object. It is measured in Newtons (N).
• Applications of Pressure:
  • Hydraulic systems (e.g., car brakes) utilize pressure to transmit force through fluids.
  • Snowshoes distribute weight over a larger area, reducing pressure and preventing sinking into snow.
• Real-world examples: High-pressure areas in weather systems lead to clear skies, while low-pressure areas result in storms.
• Concept of Inverse Proportionality: Inverse proportionality describes a relationship where one variable increases while the other decreases, commonly observed in physics and mathematics.

Explanation:

• The pressure is measured relative to atmospheric pressure, pressure above atmospheric pressure is positive gauge pressure and pressure below atmospheric pressure is negative gauge pressure also known as vacuum pressure.
•  Absolute pressure is the sum of gauge pressure and atmospheric pressure.

In science, a push or a pull on an object is called force.

The correct answer is Pressure.

Important Points

• Pressure (P): The force per unit area is called pressure. 
  • The SI unit of pressure is Pascal (Pa).

Pressure (P) = Force (F)/ Area (A)

• Thrust: The force acting perpendicular to the surface of the object is called thrust.
  • When any object is put into the water then the object will replace the water the same as it’s volume and the cause of which there is a force acting upwards, to balance this weight is called the thrust force.
  • The effect of thrust is more on the smaller surface area than the thrust acting on a larger surface area. 
• Pressure (P) = Thrust force (FT)/ Area (A)

Key Points

• Thrust is a kind of pull force, which is applied by the medium on the object.

Pressure (P) = Thrust force (F_T)/ Area (A). So option 4 is correct.

Additional Information

• Density: The mass per unit volume is called density.

The correct answer is Sleeps on the ground.

Key Points

• The pressure is inversely proportional to the area.
• As the area is maximum while lying down( unless the feet are incredibly large), therefore pressure will be minimum. 
• Pressure = Force/Area
• As, area of the surface increases, the pressure of an object always decreases.
• As the amount of force increases, the pressure also increases.

Important Points

• The unit of pressure is Pascal.
• The atmospheric pressure is always considered as 1 atm.
• As we move vertically upwards from the Earth the pressure decreases.

The correct answer is High pressure.

• Divers wear special suits in order to protect them from High pressure.
• The pressure increases as the depth increase.
• The pressure exerted in deep water under the sea is much greater than at the sea level. 
• So divers need a proper suit to bear that extra pressure.

The correct answer is Archimedes' Principle.

Key Points

• The upward buoyant force that is applied to a body submerged in a fluid, whether wholly or partially, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the centre of mass of the displaced fluid, according to Archimedes' principle.
• The Archimedes law, which was developed by Archimedes of Syracuse in Greece, provides the thrust force value.
• When an object is submerged in a liquid, whether completely or partially, the apparent weight loss is equal to the weight of the liquid that it has displaced. 

Important Points

• According to Bernoulli's principle, the total mechanical energy of a moving fluid, which includes the kinetic energy of the fluid's motion as well as the gravitational potential energy of elevation and pressure, remains constant.
• According to the Beer-Lambert law, there is a linear relationship between a solution's concentration and absorbance, making it possible to determine a solution's concentration by observing its absorbance.
• According to Blaise Pascal's law, a pressure change in a confined, incompressible fluid that happens at any place is distributed evenly throughout the fluid, causing the identical change to occur everywhere. 

Explanation:

Atmospheric Pressure

• Atmospheric pressure is the pressure at any point on the surface of the earth due to the weight of the column of air above that point.
• Air is an extremely compressible gas having its own weight.
• The pressure exerted by air due to its weight is called atmospheric pressure on the Earth’s surface.
• The Atmospheric pressure at sea level is 1 atm.
• Atmospheric pressure is commonly measured with a barometer.
• Atmospheric pressure is described by meteorologists as to how high the mercury rises.
• The standard (symbol: atm) is a unit of atmospheric pressure.
• Barograph is used for continuous recording of atmospheric pressure.

Additional Information

• It can be measured using mercury in the equation: 

Atmospheric pressure = density of mercury x acceleration due to gravity x-height of the column of mercury.

• A pascal is a pressure of one newton per square meter.

Explanation:

To drink lemonade with the help of a straw, astronauts have to make the pressure inside the moon less than the atmospheric pressure.

The correct answer is option 1 i.e., More than atmospheric pressure.

Key Points

• The pressure inside the soap bubble is more than atmospheric pressure.
• This pressure difference is assisted by the bubble’s surface tension.
• Both surfaces of inside and outside contributors.
• The pressure difference depends on the surface tension and the bubble’s radius.
• Hence, for the same liquid, a smaller bubble can support a larger pressure difference.

The correct option is decreases.

 Key Points

• Atmospheric pressure affects the boiling point of water.
• The boiling point increases as atmospheric pressure increases; on the other hand, the boiling point decreases when atmospheric pressure decreases with elevation.
• When pressure is applied to the water's surface, the molecules of the liquid are typically held in place.
• The number of gas molecules in the air decreases with height, making the air less dense than air closer to sea level.

Additional Information

Boiling Point:

• The temperature at which a liquid's vapor pressure equals the pressure of the gas above it is known as the boiling point of the liquid.
• The temperature at which a liquid's vapor pressure equals one atmosphere is considered the liquid's typical boiling point (760 torrs).

Atmospheric Pressure:

• It is the force that the air above a surface applies to it while gravity pulls the surface toward Earth.
• A barometer is frequently used to measure atmospheric pressure.

Vapor Pressure:

• Vapour pressure rises with temperature and is a measurement of a substance's propensity to transform into a gaseous or vapor state.