Explanation

• A black hole has an extremely strong gravitational field.
• Its gravity is so powerful that even light cannot escape from it.
• Black holes are formed when very massive stars collapse after exhausting their fuel.
• The boundary beyond which nothing can escape is called the event horizon.
• The idea of black holes comes from Einstein's General Theory of Relativity (1915).

Last verified on 08-07-2026

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

• The laws of magnetic induction were given by Michael Faraday.
• Faraday proposed these laws in 1831 after discovering electromagnetic induction.
• The laws explain that a changing magnetic field induces an electromotive force (EMF) in a conductor.
• These laws are the foundation of electric generators and transformers.

Last verified on 06-07-2026

Explanation

• Karl Landsteiner discovered the ABO Blood Group System in 1900.
• He was an Austrian scientist and physician.
• His discovery made safe blood transfusions possible.
• He received the Nobel Prize in Physiology or Medicine in 1930 for his work.

Last verified on 01-07-2026

Explanation

• The magnitude of an earthquake is measured by the Richter scale.
• It measures the energy released by an earthquake.
• The Richter scale was developed in 1935 by Charles F. Richter.
• It is used in seismology (the study of earthquakes).

Last verified on 30-06-2026

Explanation

• William Harvey discovered the circulation of blood in 1628.
• He was the first physician to completely describe systemic blood circulation.
• Famous book: De Motu Cordis (On the Motion of the Heart and Blood) (1628)
• He is known as the Father of Circulation of Blood.

Additional information:

• Birth: 1578
• Death: 1657

Last verified on 23-06-2026

Explanation

• Name: Waldemar Haffkine
• Year: 1892
• Vaccine: Cholera vaccine (first effective form)
• Place of work: India (British India)
• Field: Microbiology / Immunology

Last verified on 23-06-2026

Explanation

• Neon gas was discovered by William Ramsay and Morris Travers in 1898.
• It was found during the study of liquefied air and noble gases.
• Neon is a noble gas.
• It is chemically inert (does not react easily).
• It is famous for producing bright reddish-orange light in neon signs.
• It is present in very small amounts in Earth’s atmosphere.

Last verified on 21-06-2026

Explanation

• Theory proposed by: Charles Darwin
• Book published: 1859
• Book name: On the Origin of Species
• Key concept: Natural Selection
• Voyage that inspired him: HMS Beagle expedition (1831–1836)

Last verified on 21-06-2026

Explanation

• Ibn Zakariya Al-Razi is considered the father of Pediatrics (Child healthcare).
• He was a famous Muslim physician, philosopher, and scientist.
• Field: Medicine, Chemistry, Philosophy
• Known as: Rhazes
• Famous books: Al-Hawi, Kitab al-Mansuri

Last verified on 09-06-2026