Explanation

• A Fathometer is used to measure the depth of the ocean, sea, or any body of water.
• It determines the distance from the water surface to the seabed.
• The instrument works using sound waves (echo sounding).
• It measures the time taken for sound waves to travel to the seabed and return.

Additional information:

• Galvanometer → Measures electric current
• Barometer → Measures atmospheric pressure
• Thermometer → Measures temperature
• Hygrometer → Measures humidity

Last verified on 06-07-2026

Explanation

• Sir James Chadwick discovered the neutron in 1932.
• He was a British physicist.
• His discovery completed the basic picture of the atomic nucleus.
• He received the Nobel Prize in Physics in 1935 for this discovery.

Additional information:

• J. J. Thomson – Electron (1897)
• Ernest Rutherford – Atomic nucleus (1911) and Proton (1917)

Last verified on 03-07-2026

Explanation

• The hottest planet in our solar system is Venus.

Additional information:

• The black planet is called Venus.
• The second-closest planet to the Sun is Venus.
• Slowest Rotating Planet
• No moon
• Similar in size to Earth

Last verified on 30-03-2026

Explanation

• Diamond is a naturally occurring allotropic form of carbon.
• Allotropy means a single element can exist in more than one form with different structures and properties.
• It is extremely hard.
• It has a high melting point.
• It is widely used in jewelry and cutting tools.

Additional information:

• Graphite – soft, good conductor
• Fullerenes (C60) – spherical molecules
• Carbon nanotubes – tubular, high strength
• Amorphous carbon – coal, soot
• Lonsdaleite – hexagonal diamond

Last verified on 17-01-2026

Explanation

• Between the melting point and boiling point, a substance exists in the liquid state.
• At melting point, solid changes into liquid.
• At boiling point, liquid changes into gas.
• So in between these two points, the substance remains stable as a liquid.

Last verified on 20-06-2026

Explanation

• Total standard zones: 24
• Earth rotation time: 24 hours
• Longitude per zone: 15 degrees
• Starting point: Greenwich (0°)
• It is used worldwide for time coordination.

Last verified on 14-06-2026

Explanation

• The hardness of water is mainly caused by the presence of calcium (Ca²⁺) and magnesium (Mg²⁺) ions.
• These ions react with soap and reduce its ability to form foam.
• Hard water commonly contains dissolved salts of calcium and magnesium.
• Temporary hardness is mainly due to bicarbonates.
• Permanent hardness is due to sulfates and chlorides.
• Water hardness is measured in terms of calcium carbonate (CaCO₃) equivalent.

Last verified on 14-06-2026

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

• Fluorine (F₂) is the strongest oxidizing agent among the halogens.
• It has the highest tendency to gain electrons due to its high electronegativity.
• Oxidizing power decreases down the halogen group.
• The order is: F₂ > Cl₂ > Br₂ > I₂.
• Fluorine reacts very easily with other elements.

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