š Class 9 ā Science
Q. What is matter?
Ans: Matter is anything that has mass and occupies space.
Q. Name three states of matter.
Ans: Solid, liquid and gas.
Q. What is diffusion?
Ans: Diffusion is mixing of particles on their own.
Q. Which state has maximum space?
Ans: Gaseous state has maximum space.
Q. What is evaporation?
Ans: Evaporation is change of liquid into gas.
Q. What happens during melting?
Ans: Solid changes into liquid.
Q. Define condensation.
Ans: Gas changes into liquid.
Q. What is density?
Ans: Density is mass per unit volume.
Q. Which state is most compressible?
Ans: Gases are most compressible.
Q. Why do gases diffuse fast?
Ans: Because particles move freely.
Q. What is matter?
Ans: Anything that has mass and occupies space.
Q. SI unit of mass?
Ans: Kilogram
Q. Law of conservation of mass?
Ans: Mass is neither created nor destroyed.
Q. What is atom?
Ans: Smallest unit of matter.
Q. What is molecule?
Ans: Group of atoms.
Q. Unit of force?
Ans: Newton
Q. Acceleration due to gravity?
Ans: 9.8 m/sĀ²
Q. Which gas used in respiration?
Ans: Oxygen
Q. What is tissue?
Ans: Group of similar cells.
Q. Plant transport tissue?
Ans: Xylem and phloem