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

• 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

Explanation

• The Moon's surface gravity is about 1/6th as powerful or about 1.6 meters per second.
• The Moon's surface gravity is weaker because it is far less massive than Earth.
• A body's surface gravity is proportional to its mass, but inversely proportional to the square of its radius.

Last verified on 13-03-2026

Explanation

• The invention of the Lever is attributed to Archimedes.
• The lever was first described in 260 B.C.E. by Archimedes.

Last verified on 13-03-2026

Explanation

• 1 kilogram (Kg) = 1000 grams (g)
• So, 0.2 Kg = 0.2 × 1000 g = 200 g
• Mass is a measure of matter in an object.

Last verified on 13-03-2026

Explanation

• Acceleration is not a base quantity.

The base quantities are:

• Length (L)
• Mass (M)
• Time (T)

Last verified on 13-03-2026

Explanation

• Thermodynamics studies the relationship between heat, temperature, energy, and work.

Additional information:

• First law: Energy cannot be created or destroyed (Law of energy conservation)
• Second law: Heat flows from hot to cold spontaneously
• Third law: Absolute zero cannot be reached
• Zeroth law: Establishes temperature measurement
• Applications: Engines, refrigerators, heat pumps, and power plants

Last verified on 13-03-2026

Explanation

• A thermal conductor is a material that allows heat to pass through it easily.
• Metals like copper, aluminum, and iron are good thermal conductors.
• Thermal conduction occurs mainly in solids where particles are closely packed.
• In contrast, thermal insulators (like wood, plastic, and rubber) resist heat flow.

Last verified on 13-03-2026