Explanation

• Rear view mirrors in vehicles are convex mirrors.
• They give a wider field of view.
• Images formed are virtual, upright, and smaller.
• This helps drivers see more traffic behind them.
• It is a curved mirror that bulges outward.
• It is commonly used in side mirrors of cars, buses, and motorcycles.

Last verified 26-04-2026

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

• Saturn is the second-largest planet in the solar system.
• Ganymede (Moon of Jupiter) is the largest satellite in the solar system.

Planets and Natural Satellites:

1. Mercury: 0
2. Venus: 0
3. Earth: 1 (Moon)
4. Mars: 2 (Deimos, Phobos)
5. Jupiter: 95
6. Saturn: 274
7. Uranus: 27

Last verified on 02-05-2026

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

• Light Year is the distance that light can travel in one year.
• The distance light travels in one year is known as light year.
• 1 light year is equal to 9.5 x 10¹²km.

Last verified on 30-03-2026

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