The statement Particles of matter are continuously moving should be considered:

Introduction / Context:
This question is from basic physics and chemistry and is linked to the kinetic theory of matter. It asks you to evaluate the statement that particles of matter are continuously moving. Understanding this concept helps explain diffusion, changes of state, temperature, and many observable phenomena in everyday life, such as smell spreading in a room or sugar dissolving in water.

Given Data / Assumptions:

• The statement asserts continuous motion of particles in matter.
• The options ask whether this is correct or incorrect and in which states of matter it applies.
• School level knowledge of particle motion in solids, liquids, and gases is assumed.

Concept / Approach:
According to the particle model and kinetic theory, matter is made up of tiny particles that are always in motion. In solids, particles vibrate about fixed positions but do not remain perfectly still. In liquids, particles can move past each other while remaining close together, which allows liquids to flow. In gases, particles move freely and rapidly in all directions, occupying the available space. Even at low temperatures above absolute zero, these particles retain some kinetic energy and therefore keep moving. Only at absolute zero, an ideal limit that is practically unreachable, would particle motion theoretically cease. Thus, the general statement that particles of matter are continuously moving is correct for all common states of matter under normal conditions.

Step-by-Step Solution:

Verification / Alternative check:
Textbooks in science often illustrate diffusion of bromine vapour or perfume in a room and diffusion of potassium permanganate in water to show that particles of gases and liquids are constantly moving and mixing. They also describe Brownian motion, where tiny pollen grains or dust particles in water jiggle randomly because they are continuously bombarded by moving water molecules. These demonstrations provide direct evidence that particles of matter are in continuous motion even when the bulk material appears still. Although we do not see individual atoms moving, their motion is inferred from such experiments and matches the kinetic theory, confirming that the statement is correct for solids, liquids, and gases.

Why Other Options Are Wrong:

Incorrect, because only gas particles move while solid and liquid particles remain fixed is wrong because solids have vibrating particles and liquids have moving particles that allow them to flow.

Incorrect, because particles move only when an external force is applied is incorrect; thermal energy alone causes continuous random motion even without visible forces.

Correct only for liquids and gases but not for solids is also wrong because even in solids, particles vibrate around fixed positions, so motion is still present at the microscopic level.

Common Pitfalls:
Students often imagine solids as perfectly rigid blocks with particles frozen in place, which leads them to deny motion in solids. Another pitfall is to confuse visible motion of objects with invisible motion of particles, assuming that a still object means its particles are still. To avoid these misconceptions, remember that particles in all states of matter constantly move due to their kinetic energy, so the statement in the question is correctly describing the particle model of matter.