Which statement about plasma is true?

• A. It occurs at extremely low temperatures and is neutral.
• B. It occurs at extremely high temperatures and is ionized.
• C. It is a solid at room temperature.
• D. It has a definite shape and volume.

Answer: (B)

Plasma is a state of matter made of charged particles—ions and free electrons—created when enough energy ionizes atoms. This means the atoms are stripped of electrons, so there are free charges that conduct electricity and respond to magnetic fields. Because of these free charges, plasma behaves unlike a solid or liquid; it doesn’t have a definite shape or volume and will fill the space it's in, much like a gas. It also isn’t neutral; it contains both positive ions and electrons. The need for very high temperatures or strong energy input to produce ionization is why the correct statement describes plasma as arising at extremely high temperatures and being ionized. Real-world examples include the sun and stars, lightning, and neon signs.