Class 9 Physics MCQs: Density And Temperature

MCQs (sample)

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

1. 1. What does the temperature of a substance measure?

   • Its hotness or coldness
   • Its total mass
   • The volume of its particles
   • The number of particles
   Answer & explanation

   Correct: Its hotness or coldness

   Temperature measures the hotness or coldness of a substance.

2. 2. What is density defined as?

   • Mass per unit volume of the substance
   • Volume per unit mass of the substance
   • Weight per unit area of the substance
   • Mass per unit time of the substance
   Answer & explanation

   Correct: Mass per unit volume of the substance

   Density is defined as mass per unit volume of the substance.

3. 3. What are the three fundamental states of matter?

   • Solid, Liquid, Gas
   • Solid, Plasma, Liquid
   • Liquid, Gas, Plasma
   • Solid, Liquid, Matter
   Answer & explanation

   Correct: Solid, Liquid, Gas

   The three fundamental states of matter are solid, liquid, and gas.

4. 4. What happens to the average kinetic energy of particles when a substance is heated?

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

   Correct: It increases

   Heating a substance increases the speed and kinetic energy of its particles, leading to increased average kinetic energy.

5. 5. Which unit is commonly used to measure density?

   • Kilogram per cubic metre (kg/m³)
   • Meter per second (m/s)
   • Kilogram per litre (kg/L)
   • Gram per square metre (g/m²)
   Answer & explanation

   Correct: Kilogram per cubic metre (kg/m³)

   The SI unit for density is kilogram per cubic metre (kg/m³).

6. 6. What holds the particles in a solid together?

   • Strong attractive force
   • Weak attractive force
   • No attractive force
   • Repulsive force
   Answer & explanation

   Correct: Strong attractive force

   Solids are held together by a strong attractive force between their particles.

7. 7. What is absolute zero?

   • The highest temperature of a substance
   • The lowest possible temperature of a substance
   • The normal room temperature
   • A temperature where all particles are in motion
   Answer & explanation

   Correct: The lowest possible temperature of a substance

   Absolute zero is defined as the lowest possible temperature where particles have least kinetic energy.

8. 8. What is the density of gold according to Table 7.1?

   • 19300 kg/m³
   • 7900 kg/m³
   • 1000 kg/m³
   • 920 kg/m³
   Answer & explanation

   Correct: 19300 kg/m³

   The density of gold is listed as 19300 kg/m³ in Table 7.1.

9. 9. How do the particles in liquids move?

   • They vibrate about fixed positions.
   • They flow and glide over each other.
   • They are stationary.
   • They explode randomly.
   Answer & explanation

   Correct: They flow and glide over each other.

   Liquid particles can flow and glide over each other, allowing them to change shape.

10. 10. What is the temperature value of absolute zero on the Kelvin scale?

    • 0 °C
    • 0 K
    • -273.15 °C
    • 100 K
    Answer & explanation

    Correct: 0 K

    The absolute zero temperature is defined as zero kelvin (0 K).

11. 11. Which material has the lowest density according to the table provided?

    • Air
    • Ice
    • Polythene
    • Petrol
    Answer & explanation

    Correct: Air

    Air has the lowest density at 1.3 kg/m³ according to Table 7.1.

12. 12. Which state of matter has a fixed shape?

    • Solid
    • Liquid
    • Gas
    • Plasma
    Answer & explanation

    Correct: Solid

    Solids have a fixed shape due to closely packed particles.

13. 13. Which of the following is a thermometric property used in mercury thermometers?

    • Volume expansion of a gas
    • Volume expansion of a liquid
    • Pressure change of a gas
    • Change in e.m.f
    Answer & explanation

    Correct: Volume expansion of a liquid

    Mercury thermometers utilize the property of volume expansion of a liquid.

14. 14. What does the displacement method help to measure?

    • Density of liquids only
    • Density of regular solids only
    • Density of irregular shaped objects
    • Density of gases only
    Answer & explanation

    Correct: Density of irregular shaped objects

    The displacement method is used to measure the density of irregular shaped objects.

15. 15. What is the arrangement of particles in gases?

    • Regular pattern
    • Randomly arranged
    • Fixed lattice pattern
    • In layers
    Answer & explanation

    Correct: Randomly arranged

    Gas particles are randomly arranged and have weak attractive forces between them.

16. 16. What happens to the internal energy of a substance when its temperature increases?

    • It decreases
    • It remains the same
    • It increases
    • It becomes negative
    Answer & explanation

    Correct: It increases

    Increasing the temperature of a substance leads to an increase in its internal energy, which is the total energy of its particles.

17. 17. Which of the following substances has a density of 1000 kg/m³?

    • Mercury
    • Pure water
    • Ice
    • Carbon dioxide
    Answer & explanation

    Correct: Pure water

    Pure water has a density of 1000 kg/m³ as per Table 7.1.

18. 18. What is the density of gases compared to liquids and solids?

    • Higher than solids
    • Medium
    • Lower than both liquids and solids
    • Equal to liquids
    Answer & explanation

    Correct: Lower than both liquids and solids

    Gases have a lower density than liquids and solids.

19. 19. What are fixed points in the calibration of a thermometer?

    • The freezing and boiling points of a substance
    • The temperature range of a gas
    • The type of liquid used
    • The change in resistance
    Answer & explanation

    Correct: The freezing and boiling points of a substance

    Fixed points for thermometer calibration are the melting point of ice (0°C) and the boiling point of water (100°C).

20. 20. How do you calculate the density of a liquid?

    • Mass of the liquid divided by volume of the cylinder
    • Mass of the liquid divided by volume of the liquid
    • Mass of cylinder divided by volume of liquid
    • Mass of liquid plus mass of cylinder divided by volume
    Answer & explanation

    Correct: Mass of the liquid divided by volume of the liquid

    To calculate density, you divide the mass of the liquid by its volume.

21. 21. What characterizes the movement of particles in gases?

    • Vibrate around fixed positions
    • Move slowly and steadily
    • Move quickly in all directions
    • Stay in fixed positions
    Answer & explanation

    Correct: Move quickly in all directions

    Particles in gases are in constant random motion and can move quickly in all directions.

22. 22. What does the sensitivity of a thermometer refer to?

    • Its ability to measure very high temperatures
    • Its ability to detect small changes in temperature
    • Its maximum measurement range
    • Its construction material
    Answer & explanation

    Correct: Its ability to detect small changes in temperature

    Sensitivity in thermometers refers to their ability to detect small changes in temperature.

23. 23. When measuring the density of a solid object, what is the first step?

    • Measure its volume using water
    • Calculate its density using the formula
    • Find mass of the solid object
    • Measure its length, width, and height
    Answer & explanation

    Correct: Find mass of the solid object

    The first step is to find the mass of the solid regular shaped object.

24. 24. Which state of matter is described as having high energy?

    • Solid
    • Liquid
    • Gas
    • All of the above
    Answer & explanation

    Correct: Gas

    Gas particles have the highest energy among the three fundamental states of matter.

25. 25. What type of thermometer uses the principle of volume expansion of a solid?

    • Constant pressure gas thermometer
    • Laboratory thermometer
    • Bi-metallic strip thermometer
    • Resistance thermometer
    Answer & explanation

    Correct: Bi-metallic strip thermometer

    A bi-metallic strip thermometer works based on the volume expansion of a solid.