Explanation

• Alexander Graham Bell is credited as the inventor of the telephone.
• He was awarded the first successful patent for it.
• The telephone was invented in 1876.
• Bell made the first-ever telephone call to his assistant Thomas Watson.

Last verified on 31-03-2026

Explanation

• The Montgolfier brothers, Joseph-Michel and Jacques-Étienne, invented the hot-air balloon.
• Their first public demonstration took place in Annonay, France, on 4 June 1783.
• In 1783, a hot-air balloon carrying passengers successfully flew near Paris.
• The Montgolfier brothers are regarded as pioneers of human flight.

Last verified on 02-09-2026

Explanation

• Ibn al-Haytham presented the theory of reflection and refraction of light.
• He is also known as Alhazen.
• His work, particularly his "Book of Optics", is titled Kitab al-Manazir, written during 1011–1021.
• Born: c. 965 (c. 354 AH) Basra, Buyid Emirate
• Died: c. 1040 (c. 430 AH)[1] (aged around 75) Cairo, Fatimid Caliphate

Last verified on 02-09-2026

Explanation

• The term “antigen” was coined in 1899 by Ladislas Deutsch (László Detre).
• The word is derived from “antibody-generating” (anti + gen).

Additional information:

• Louis Pasteur is famous for his work on vaccination and germ theory.
• Edward Jenner pioneered the smallpox vaccine.

Last verified on 01-09-2026

Explanation

Sandra Harding

• Developed feminist epistemology; identified three approaches:
• Feminist empiricism (1986, The Science Question in Feminism)
• Standpoint theory (1991, Whose Science? Whose Knowledge?)
• Postmodern feminism (1986, later works)

Additional information

• Simone de Beauvoir — The Second Sex (1949)
• Judith Butler — Gender Trouble (1990)
• Betty Friedan — The Feminine Mystique (1963)

Explanation

• First man who travelled in Space was Yuri Gagarin in 1961.
• Yuri Gagarin was a Soviet pilot and cosmonaut.
• He aboard the first successful crewed spaceflight, became the first human to journey into outer space.

Additional information:

• First man who Walk in Space was Alexei Leonov in 1965.
• First man who Walk on Moon was Neil Armstrong in 1969.

Last verified on 10-03-2026

Explanation

Very high frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz,

with corresponding wavelengths of ten to one meter.

ND17-7-2023

Explanation

China has successfully landed a robot on the surface of Mars on 15 May 2021.

China has become the third country after Russia and the United States of America in history

The rover 'Zhurong' will spend around 90 Martian days on the planet.

A Martian day is around 24 hours and 39 minutes.

This rover is named after the mythical Chinese god of fire.

Explanation

Isaac Newton formulated the law of universal gravitation, explaining how gravity works.

He famously described gravity after observing an apple fall from a tree.

Explanation

• William Harvey discovered the circulation of blood.
• 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