Explanation

• Sound waves are mechanical waves that require a medium (air, water, or solid) to travel.
• They transport energy, not matter.
• Particles of the medium vibrate around their mean position but do not move along with the wave.
• Examples: Speaking, music, and alarms transfer energy through sound waves.

Last verified on 13-03-2026

Explanation

• Refraction: Bending of light when it passes from one medium to another.
• A prism bends light at different angles depending on wavelength.
• This separation of colors is called dispersion, forming a spectrum.
• Visible spectrum colors: Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).

Last verified on 13-03-2026

Explanation

Thermal energy can be transferred through all three methods:

• Conduction: Direct transfer between particles in physical contact.
• Convection: Transfer through the movement of fluids.
• Radiation: Transfer through electromagnetic waves (e.g., light, radio waves).

Last verified on 13-03-2026

Explanation

• A molecule is the smallest particle of a substance that retains its chemical properties.
• It is made of two or more atoms chemically bonded together.
• Examples of molecules: H₂O, O₂, CO₂, NH₃, CH₄.

Additional information:

• An atom is the smallest unit of an element.
• A compound is a substance formed when different elements combine chemically.

Last verified on 13-03-2026

Explanation

• According to the Kinetic Molecular Theory, faster gas particles hit container walls more often.
• More frequent and stronger collisions increase the pressure.
• Higher temperature → higher particle speed → higher pressure.
• Pressure depends on number of collisions of gas molecules with container walls.
• Unit of gas pressure: Pascal (Pa).

Last verified on 13-03-2026