Explanation

• Base Quantity: Length
• SI Unit: meter (m)
• Type: Fundamental quantity
• System: International System of Units (SI)

Additional information:

Base Quantities in SI System:

• Mass (kilogram)
• Time (second)
• Electric current (ampere)
• Temperature (kelvin)

Last verified on 16-06-2026

Explanation

• Fusion of hydrogen nuclei releases the most energy per unit mass.
• In nuclear fusion, light hydrogen nuclei combine to form helium and release huge amounts of energy.
• Fusion converts a small amount of mass into energy according to Einstein’s equation (E = mc²).
• It powers stars, including the Sun.

Last verified on 14-06-2026

Explanation

• The Aufbau Principle explains the order in which electrons fill atomic orbitals (lowest energy first).
• Electrons first occupy lower energy levels before moving to higher ones.
• This helps build the correct electronic configuration of atoms.
• It follows increasing energy order of orbitals.
• Example order: 1s → 2s → 2p → 3s → 3p → 4s …

Last verified on 14-06-2026

Explanation

• Moho discontinuity is the boundary between the Earth’s crust and mantle.
• It was discovered by seismologist Andrija Mohorovičić in 1909.
• It is identified by a sudden change in seismic wave speed.
• The crust is solid outer layer, while the mantle lies beneath it.
• Depth varies from 5–70 km depending on land or ocean area.

Last verified on 02-04-2026

Explanation

• The faint Young Sun paradox is resolved mainly by high greenhouse gas concentrations in early Earth’s atmosphere.
• Early Sun was about 70–75% as bright as today, so Earth should have frozen.
• But gases like CO₂, methane, and water vapor trapped heat effectively.
• This greenhouse effect kept Earth warm enough for liquid water.

Last verified on 14-06-2026