What is the difference between plasma, semi-liquid state & molten state?

The main difference is that the molten state is a true liquid formed by heating a solid, a semi-liquid is a mixture that behaves like both a solid and a liquid, and plasma is a distinct state of matter made of ionized gas.

Molten State 

The molten state simply refers to a substance that has been turned into a liquid by heating it above its melting point. The term is most often used for materials that are solid at room temperature, like metals, rocks, or salts.

• Composition: It consists of neutral atoms or molecules that are free to move past one another.
• Formation: Achieved by adding heat energy to a solid.
• Key Property: It is a true liquid with definite volume but no fixed shape.
• Example: Molten iron in a steel mill, lava from a volcano, or molten glass.

Semi-liquid State

A semi-liquid is not a fundamental state of matter but a descriptive term for substances that have properties of both solids and liquids. These are often thick, viscous mixtures (like colloids or suspensions) that can hold their shape to some degree but can also flow.

• Composition: A mixture of solid particles suspended in a liquid, or a complex network of molecules.
• Formation: Occurs by mixing substances.
• Key Property: High viscosity; it does not flow easily like a true liquid.
• Example: Mud, slime, gel, tar, or ketchup.

Plasma 

Plasma is considered the fourth fundamental state of matter, after solid, liquid, and gas. It is the most abundant state of matter in the universe.

• Composition: It is an ionized gas, meaning it's a "soup" of positively charged ions (atoms that have lost electrons) and free-moving, negatively charged electrons.
• Formation: Created by heating a gas to extremely high temperatures or applying a strong electromagnetic field.
• Key Property: It is electrically conductive and responds strongly to magnetic fields.
• Example: Lightning, the stars (including our Sun), the aurora borealis, and the gas inside a neon sign or plasma TV.