Explanation

• Humidity is the measure of the amount of moisture (water vapour) in the air.
• A hygrometer is used to measure relative humidity.
• A psychrometer is an example of a hygrometer.
• Relative humidity tells us the ratio of water vapour present in the air compared with the maximum amount the air can hold at a given temperature.
• Humidity is commonly expressed as a percentage (%).

Last verified on 23-08-2026

Explanation

• The law of universal gravitation was proposed by Isaac Newton.
• He introduced it in 1687 in his famous book Principia.
• It explains that every object attracts every other object.
• The force depends on mass and distance.

Last verified on 27-04-2026

Explanation

• Ozone (O₃) is mainly found in the Stratosphere, called the ozone layer.
• It absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.
• Located roughly 15–35 km above the Earth’s surface.

Last verified on 17-01-2026

Explanation

• Urine is produced in the kidneys by filtering the blood.
• The kidneys remove excess water, salts, and waste products from the blood.
• Urine is formed in tiny filtering units called nephrons.
• After formation, urine passes through the ureters to the urinary bladder.
• The kidneys help maintain the body's fluid and electrolyte balance.

Last verified on 04-08-2026

Explanation

• Sunlight travels at the speed of light (~3 × 10⁸ m/s).
• Takes 8 minutes 20 seconds on average to reach Earth.
• Sunlight takes approximately 499 seconds to travel from the Sun to Earth.
• Distance traveled: 150 million km from Sun to Earth.
• Moonlight takes only 1.3 seconds to reach Earth.

Last verified on 13-03-2026

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

• O⁻ (O Negative) is the universal donor blood group.
• It can be transfused to A, B, AB, and O blood groups.
• O⁻ blood lacks A, B, and Rh (D) antigens.

Additional information:

• Universal Recipient: AB⁺ (AB Positive)
• ABO Blood Groups: A, B, AB, O
• Rh Types: Positive (+) and Negative (−)
• Total Common Blood Groups: 8 (A⁺, A⁻, B⁺, B⁻, AB⁺, AB⁻, O⁺, O⁻)

Last verified on 14-07-2026

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

• Nitrogen (N₂): 78%

Additional information:

• Oxygen (O₂): 21%
• Argon (Ar): 0.93%
• Carbon dioxide (CO₂): ~0.04%
• Other gases: ~0.03%

Last verified on 16-05-2026

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