Explanation

• Zero error is a Systematic error because it causes a consistent error in every measurement.
• It occurs when an instrument does not read zero even when no quantity is being measured.
• The same error is repeated in all readings unless corrected.
• Zero error may be positive or negative.
• It can be corrected by applying a zero correction.

Last verified on 06-07-2026

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 density of gases increases when pressure is increased because gas molecules come closer together.
• Density is the mass per unit volume of a substance.
• When pressure increases, the volume of gas decreases (at constant temperature), causing density to increase.
• This relationship follows Boyle’s Law.

Last verified on 21-06-2026

Explanation

• The movement of water from higher water potential to lower water potential is called osmosis.
• It occurs through a semi-permeable membrane.
• Only water molecules move in osmosis.
• It is a passive process (no energy required).

Last verified on 18-06-2026

Explanation

• Solar and wind energy are renewable sources of energy, meaning they are sustainable and will not run out.
• Solar energy is generated from the sun's rays.
• Wind energy is generated from the wind.

Last verified on 09-02-2026