Explanation

• Wavelength is the distance between two successive crests or two successive troughs in a transverse wave.
• It represents one complete cycle of a wave.

Additional information:

• Symbol used: λ (Lambda)
• SI unit: meter (m)
• Wave formula: v = fλ
• Example wavelength values: 1 m, 0.5 m, 10 cm, 500 nm, 700 nm
• Visible light wavelength range: ~400 nm – 700 nm

Last verified on 12-03-2026

Explanation

• Melting of ice is a physical change, as it only involves a change in state (from solid to liquid) without a change in chemical composition.

The examples of chemical changes:

• Burning of fuel
• Explosion of firework
• Burning of wood
• Cooking of food (breakfast, lunch, dinner)
• Bursting of crackers
• Burning of wax
• Rusting of iron
• Heating sulphur with iron fillings (to produce iron sulphide)
• Digestion of food
• Respiration in living things
• Photosynthesis in plants

Last verified on 09-03-026

Explanation

• Protons and neutrons form the nucleus of an atom.
• Together, they are called nucleons because they are nuclear particles.

Additional information:

• Nucleons determine the mass of an atom.
• Isotopes are atoms of the same element with different number of neutrons.

Last verified on 07-03-2026

Explanation

• Xylem is the plant tissue responsible for transporting water and minerals from roots → stem → leaves.
• It consists of continuous tubes made of dead cells for easy water flow.

Additional information:

• Phloem: Transports food (sugars) from leaves to other parts

Explanation

Our solar system takes approximately 225 to 230 million Earth years to complete one full orbit around the center of the Milky Way galaxy,

A period known as a galactic year or cosmic year. 

Traveling at about 514,000 mph (828,000 km/h)

Given the Sun's age, it has circled the galactic center about 20 times. 

Explanation

Explanation

• Veins are the blood vessels that carry blood from other parts of the body back to the heart.
• They have one-way valves that prevent blood from flowing backwards and ensure it keeps moving towards the heart.

Explanation

• Dust and gas in the interstellar medium (ISM) can absorb and scatter starlight.
• It leading to a reduction in the brightness of stars as seen from Earth.
• This is known as interstellar extinction.

Explanation

• Red stars, also known as red dwarfs, typically have a surface temperature around 3000°C (5400°F).
• This is the coolest temperature range for stars, and it's what gives them their distinctive red color.

Explanation

• Heat is a form of energy that flows from a region of high temperature to a region of low temperature.
• This flow of energy occurs through the transfer of kinetic energy from particles in motion.