Lesson 4.1.1

4.1.1 Density and upthrust Quiz: Pearson Edexcel Physics, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.1.1, Density and upthrust: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 4: Materials, written with Revision Ninja.

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The 20 questions

  1. What is density?

    • Volume per unit mass, in m^3/kg
    • Mass per unit volume, in kg/m^3
    • Mass per unit area, in kg/m^2
    • Force per unit area, in N/m^2

  2. According to Archimedes' principle, what is the upthrust on a body wholly or partly immersed in a fluid?

    • The pressure at the top of the body multiplied by its area
    • The weight of the fluid displaced by the body
    • The mass of fluid lying directly above the body
    • The weight of the body

  3. Why does a fluid exert an upthrust on a submerged object?

    • The object is less dense than the fluid, so it is pushed up
    • Fluid molecules attract the object upwards
    • Pressure is equal on all faces, so the net force is upward
    • Pressure increases with depth, so the force on the lower face is greater than the force on the upper face

  4. A solid floats at rest in equilibrium. Which statement is true?

    • Its upthrust is zero
    • Its upthrust equals its weight
    • Its density is zero
    • Its upthrust is greater than its weight

  5. A floating object has density rho_o and the fluid has density rho_f. What fraction of the object's volume is submerged?

    • rho_o/rho_f
    • rho_f/rho_o
    • rho_o x rho_f
    • 1 - rho_o/rho_f

  6. Approximately what is the density of pure water?

    • 100 kg/m^3
    • 1 kg/m^3
    • 1000 kg/m^3
    • 10000 kg/m^3

  7. A fully submerged body experiences an upthrust that depends on which quantities?

    • The mass of the body and the density of the fluid
    • The surface area of the body only
    • The depth of the body and the mass of the body
    • The volume of the body and the density of the fluid

  8. A block has mass 2.0 kg and volume 4.0 x 10^-3 m^3. What is its density?

    • 500 kg/m^3
    • 0.002 kg/m^3
    • 8000 kg/m^3
    • 2000 kg/m^3

  9. An object of volume 2.0 x 10^-4 m^3 is fully submerged in water of density 1000 kg/m^3. What is the upthrust? Take g = 9.8 N/kg.

    • 20 N
    • 0.20 N
    • 0.98 N
    • 2.0 N

  10. A floating block has density 600 kg/m^3 and floats in water of density 1000 kg/m^3. What percentage of its volume is submerged?

    • 167%
    • 40%
    • 600%
    • 60%

  11. A block of density 800 kg/m^3 has volume 0.050 m^3. What is its weight? Take g = 9.8 N/kg.

    • 390 N
    • 40 N
    • 4.0 N
    • 1600 N

  12. A block weighing 3.0 N floats with half of its volume submerged. What is the upthrust on it?

    • 1.5 N
    • 0 N
    • 3.0 N
    • 6.0 N

  13. An object weighs 5.0 N in air. It is fully submerged in water with volume 1.0 x 10^-4 m^3. What is its apparent weight in water? Take g = 9.8 N/kg.

    • 5.0 N
    • 6.0 N
    • About 4.0 N
    • 0.98 N

  14. A cube of mass 0.27 kg has side length 0.10 m. What is its density?

    • 27 kg/m^3
    • 270 kg/m^3
    • 2.7 kg/m^3
    • 2700 kg/m^3

  15. An object floats in oil of density 800 kg/m^3 with 75% of its volume submerged. What is its density?

    • 1067 kg/m^3
    • 600 kg/m^3
    • 800 kg/m^3
    • 200 kg/m^3

  16. A solid denser than water is fully submerged and released. Why does it sink?

    • The upthrust is zero once the object is below the surface
    • Its upthrust is greater than its weight, so it accelerates downwards
    • Its weight exceeds the maximum upthrust, so the net force is downwards
    • Both forces are zero, so the object stays at rest at the bottom

  17. A 2.0 kg object of density 500 kg/m^3 is fully submerged in water of density 1000 kg/m^3. What is the net force on it? Take g = 9.8 N/kg.

    • 19.6 N downward
    • 19.6 N upward
    • 58.8 N upward
    • 39.2 N upward

  18. A student claims that upthrust depends on the density of the object. Which evaluation is correct?

    • Upthrust depends on the fluid density and the volume submerged, not on the object's density
    • The claim is correct, because a floating object's upthrust equals its density
    • Upthrust depends on object density, because denser objects displace more fluid
    • Upthrust is independent of the volume submerged

  19. A block of density 2500 kg/m^3 and volume 1.0 x 10^-3 m^3 hangs from a string while fully submerged in water. What is the tension in the string? Take g = 9.8 N/kg.

    • 24.5 N
    • 34.3 N
    • 9.8 N
    • 14.7 N

  20. A 0.30 kg irregular solid has a volume of 1.5 x 10^-4 m^3 measured by displacement. What is its density?

    • 200 kg/m^3
    • 20000 kg/m^3
    • 2000 kg/m^3
    • 450 kg/m^3

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