Which of the following are fluids? Select all that apply.
A) solids
B) liquids
C) gases
D) plasmas
E) heat
The correct answer and explanation is :
Correct Answer:
B) Liquids
C) Gases
D) Plasmas
Explanation:
A fluid is any substance that can flow and take the shape of its container. Fluids have the ability to deform continuously under an applied force, which distinguishes them from solids. Let’s analyze each option:
A) Solids – Not a Fluid
Solids have a fixed shape and do not flow under normal conditions. Their particles are tightly packed in a rigid structure, which prevents them from behaving like fluids. While some solids can deform over time (such as glass flowing very slowly), they are not considered fluids because they do not exhibit continuous flow.
B) Liquids – A Fluid
Liquids are classical fluids because they can flow and take the shape of their container while maintaining a nearly constant volume. The intermolecular forces in liquids are weaker than in solids, allowing particles to move past each other while remaining in close contact. Examples include water, oil, and mercury.
C) Gases – A Fluid
Gases also qualify as fluids because they flow freely and expand to fill the shape and volume of their container. Unlike liquids, gases have no fixed volume and can be compressed easily. Their particles are widely spaced and move rapidly in all directions.
D) Plasmas – A Fluid
Plasmas, which are ionized gases consisting of free electrons and ions, behave like fluids. Found in stars and lightning, plasmas can flow and exhibit fluid-like properties. They are considered the fourth state of matter and follow similar principles to gases but with additional electromagnetic interactions.
E) Heat – Not a Fluid
Heat is a form of energy, not a substance. Since fluids must have mass and be composed of particles, heat does not qualify as a fluid. Instead, heat is transferred through conduction, convection, or radiation.
Thus, the correct answers are B, C, and D.