Explanation

• The instrument used to measure temperature is called a thermometer.
• A thermometer shows how hot or cold an object or place is.

Additional information:

• Barometer measures air pressure.
• Hygrometer measures humidity (moisture in air).

Last verified on 16-06-2026

Explanation

• The Sun is the ultimate and main source of energy on Earth.
• It provides energy through solar radiation (light and heat).
• All forms of energy on Earth directly or indirectly come from the Sun.
• It supports life, climate, and ecosystems on Earth.

This energy is then converted into various forms, such as:

• Thermal energy (heat)
• Kinetic energy (wind, water currents)
• Electrical energy (generated from solar panels)
• Chemical energy (fossil fuels, biomass)
• Biological energy (food chains, ecosystems)

Last verified on 16-06-2026

Explanation

• The human body contains about 65% oxygen by mass.
• Oxygen is the most abundant element in the human body.
• It is mainly present in water (H₂O) and organic compounds.
• It is essential for respiration and energy production.

Additional information:

• Carbon: ~18%
• Hydrogen: ~10%
• Nitrogen: ~3%
• Other elements: ~4% (calcium, phosphorus, etc.)

Last verified 09-06-2026

Explanation

When white light passes through a prism, it splits into 7 colors, forming a spectrum known as a rainbow:

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Indigo
7. Violet

The separation of visible light into its different colours is known as dispersion.

Last verified on 08-06-2026

Explanation

• Sublimation is the direct transition of a solid into a gas without passing through the liquid phase.

Additional information:

Some common sublimating substances:

• Dry ice (CO₂) – solid → gas
• Iodine crystals – solid → violet gas
• Camphor – solid → vapor
• Naphthalene (mothballs) – solid → gas
• Ammonium chloride – solid → gas

Last verified on 13-03-2026