MCQ: PHYSICAL NATURE OF MATTER
- What is matter made up of?
Answer: Particles
Explanation: Matter is not continuous but is composed of tiny particles that are too small to be seen with the naked eye. This is demonstrated by dissolving substances like salt or sugar in water, where the particles mix uniformly without increasing the water level.
- What is the unit of mass in the SI system?
Answer: Kilogram
Explanation: The SI (International System of Units) unit for measuring mass is the kilogram (kg), which provides a standard reference for measuring objects worldwide.
- What is the SI unit of volume?
Answer: Cubic metre
Explanation: The standard unit for measuring volume is the cubic metre (m³), but for practical purposes, smaller units like litres (L) and millilitres (mL) are commonly used.
- Which property of matter explains why salt dissolves in water?
Answer: Space
Explanation: The particles of matter have spaces between them, which allow substances like salt or sugar to dissolve in water without increasing the overall volume significantly.
- Which property of matter explains the spreading of perfume in a room?
Answer: Diffusion
Explanation: The particles of matter are in constant motion, and their ability to spread and mix with other substances is called diffusion. This is why the smell of perfume spreads even if sprayed in one corner of the room.
- What happens to the movement of particles when temperature increases?
Answer: Increases
Explanation: When heat is applied, the kinetic energy of the particles increases, making them move faster. This is why heating a substance speeds up the rate of diffusion.
- Which state of matter has the strongest intermolecular force?
Answer: Solid
Explanation: In solids, the particles are tightly packed with strong forces of attraction between them, making solids rigid and incompressible.
- Which state of matter has the weakest intermolecular force?
Answer: Gas
Explanation: In gases, the particles are far apart with negligible intermolecular forces, allowing them to move freely and fill the entire space of a container.
- What is the process of conversion of a solid directly into a gas called?
Answer: Sublimation
Explanation: Certain substances like naphthalene and dry ice (solid CO₂) undergo sublimation, where they change directly from solid to gas without passing through the liquid state.
- What is the phenomenon where matter spreads out and intermixes on its own?
Answer: Diffusion
Explanation: Diffusion occurs in all states of matter but is fastest in gases due to the high kinetic energy of gas particles, which move freely and mix rapidly.
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