Class 9 Physics MCQs: Pressure And Deformation In Solids

MCQs (sample)

Showing 25 questions from this chapter. For a full timed test, use “Start online test”.

1. 1. What happens when we pump a bicycle tire?

   • Pressure increases equally throughout the tire
   • Only the pump's pressure increases
   • Air escapes from the tire
   • The tire becomes completely rigid
   Answer & explanation

   Correct: Pressure increases equally throughout the tire

   When we pump a bicycle tire, the pressure increases equally throughout the tire, as per Pascal's principle.

2. 2. What is the formula for pressure?

   • P = F / A
   • P = A / F
   • P = F * A
   • P = A + F
   Answer & explanation

   Correct: P = F / A

   Pressure is defined as the force applied over an area, expressed as P = F / A.

3. 3. What is elasticity?

   • The ability to return to original shape when forces are removed.
   • The ability to change shape permanently.
   • The ability to minimize deformation.
   • The ability to withstand high forces.
   Answer & explanation

   Correct: The ability to return to original shape when forces are removed.

   Elasticity is defined as the ability of a deformed body to return to its original shape and size when the deforming forces are removed.

4. 4. What is atmospheric pressure?

   • The pressure exerted by atmospheric particles on Earth’s surface
   • The pressure inside a vacuum
   • The pressure exerted by liquids only
   • The pressure exerted by solid objects
   Answer & explanation

   Correct: The pressure exerted by atmospheric particles on Earth’s surface

   Atmospheric pressure is defined as the pressure that atmospheric particles exert on the surface of the Earth and all over the surface of objects on the Earth.

5. 5. What causes liquid pressure?

   • Weight of the liquid
   • Temperature of the liquid
   • Surface area
   • Viscosity of the liquid
   Answer & explanation

   Correct: Weight of the liquid

   Liquid pressure is due to the weight of the liquid.

6. 6. What is a manometer used to measure?

   • Pressure in a fluid
   • Temperature of a fluid
   • Volume of a fluid
   • Density of a fluid
   Answer & explanation

   Correct: Pressure in a fluid

   A manometer measures the pressure in a fluid using fluid dynamics.

7. 7. According to Pascal's principle, how does pressure change in a fluid when an external pressure is applied?

   • It only changes at the point of application
   • It remains unchanged everywhere
   • It increases equally throughout the fluid
   • It decreases in other areas of the container
   Answer & explanation

   Correct: It increases equally throughout the fluid

   Pascal's principle states that an external pressure applied to an enclosed fluid is transmitted unchanged to every point within the fluid, causing equal pressure increase.

8. 8. What is the SI unit of pressure?

   • Pascal (Pa)
   • Newton (N)
   • Bar
   • Atmosphere (atm)
   Answer & explanation

   Correct: Pascal (Pa)

   The SI unit of pressure is pascal (Pa).

9. 9. Which material is mentioned as being inelastic?

   • Plasticine
   • Rubber
   • Steel
   • Glass
   Answer & explanation

   Correct: Plasticine

   Plasticine is given as an example of an inelastic material that does not return to its original shape after deformation.

10. 10. At sea level, what is the average atmospheric pressure in Pascals?

    • 1.013 x 10^5 Pa
    • 1.000 x 10^5 Pa
    • 760 mmHg
    • 101.325 kPa
    Answer & explanation

    Correct: 1.013 x 10^5 Pa

    At sea level, the atmospheric pressure is on average 1.013 x 10^5 Pa.

11. 11. In the equation P = ρhg, what does 'h' represent?

    • Density of the liquid
    • Height of the liquid column
    • Area of cross-section
    • Gravity
    Answer & explanation

    Correct: Height of the liquid column

    'h' represents the height of the liquid column in the equation for pressure.

12. 12. Which formula represents the pressure in a manometer?

    • P = ρgh
    • P = V/t
    • P = F/A
    • P = mgh
    Answer & explanation

    Correct: P = ρgh

    The formula of a manometer is P = ρgh, where P is pressure, ρ is density, g is gravitational acceleration, and h is height of fluid.

13. 13. What does the equation F = P x A represent?

    • Force is equal to pressure multiplied by area
    • Pressure is equal to force divided by area
    • Area is equal to force divided by pressure
    • Force is equal to area minus pressure
    Answer & explanation

    Correct: Force is equal to pressure multiplied by area

    The equation F = P x A represents that the force generated is equal to the pressure multiplied by the area.

14. 14. How does pressure change when force increases or area decreases?

    • Pressure decreases
    • Pressure increases
    • Pressure remains the same
    • Pressure fluctuates
    Answer & explanation

    Correct: Pressure increases

    Pressure increases when the force on a specific area is increased or when a smaller area is subjected to a given force.

15. 15. What is Hooke's law about?

    • The relationship between force and distance.
    • The relationship between extension and restoring force within elastic limits.
    • The behavior of inelastic materials under force.
    • The strength of different materials.
    Answer & explanation

    Correct: The relationship between extension and restoring force within elastic limits.

    Hooke's law states that within elastic limits, the extension (or compression) is directly proportional to the restoring force.

16. 16. What happens to atmospheric pressure as one ascends from the Earth's surface?

    • It increases
    • It decreases
    • It remains constant
    • It becomes zero instantly
    Answer & explanation

    Correct: It decreases

    The atmospheric pressure decreases as we go up from the surface of the Earth.

17. 17. What does the symbol ρ represent in liquid pressure calculations?

    • Volume of the liquid
    • Density of the liquid
    • Weight of the liquid
    • Depth of the liquid
    Answer & explanation

    Correct: Density of the liquid

    The symbol ρ represents the density of the liquid in pressure calculations.

18. 18. What does 'P' represent in the manometer equation P = ρgh?

    • Pressure of the fluid
    • Density of the fluid
    • Gravitational acceleration
    • Height of fluid
    Answer & explanation

    Correct: Pressure of the fluid

    'P' stands for the pressure of the fluid in the manometer equation.

19. 19. In a hydraulic lift, what is the relationship between F1 and F2?

    • F2 = F1
    • F2 = (A2/A1) * F1
    • F1 = (A2/A1) * F2
    • F1 = F2
    Answer & explanation

    Correct: F2 = (A2/A1) * F1

    In a hydraulic lift, the relationship is given as F2 = (A2/A1) * F1, depending on the ratio of the areas.

20. 20. Why does a balloon burst more readily when pricked with a pin than when squeezed by hand?

    • More air enters the balloon
    • The pin applies force on a smaller area, creating higher pressure
    • The pin has less force than a hand
    • The hand creates a vacuum
    Answer & explanation

    Correct: The pin applies force on a smaller area, creating higher pressure

    The force applied to the small area of the needle tip creates enough pressure to burst the balloon.

21. 21. What does the negative sign in Hooke's law formula indicate?

    • Force acts in the same direction as displacement.
    • Force is directed against displacement.
    • Force increases with compression only.
    • Force has no relation to extension.
    Answer & explanation

    Correct: Force is directed against displacement.

    The negative sign in the formula F_res = -kx indicates that the restoring force acts in the opposite direction to the displacement.

22. 22. How does a suction cup adhere to a surface?

    • Due to vacuum inside the cup
    • Due to atmospheric pressure
    • Due to static electricity
    • Due to adhesive materials
    Answer & explanation

    Correct: Due to atmospheric pressure

    A suction cup gets its sticking force because of the atmospheric pressure that holds it to the wall when air is forced out of the cup.

23. 23. If you increase the depth of a liquid, what happens to the pressure?

    • It increases
    • It decreases
    • It stays the same
    • It depends on temperature
    Answer & explanation

    Correct: It increases

    The pressure in a liquid increases with depth.

24. 24. Which component of the manometer is open to atmospheric pressure?

    • One end
    • Both ends
    • The connecting tube
    • The fluid inside
    Answer & explanation

    Correct: One end

    One end of the manometer is connected to a seal-tight gas, while the other end is open to atmospheric pressure.

25. 25. What does the term 'hydraulic fluid' refer to in a hydraulic lift?

    • The air in the tire
    • The fluid that transmits pressure
    • The liquid that cools down the system
    • The substance used to lubricate the pistons
    Answer & explanation

    Correct: The fluid that transmits pressure

    Hydraulic fluid refers to the fluid that transmits pressure in a hydraulic lift system.