Explanation

• Discoverer: Alexander Fleming
• Year of discovery: 1928
• Place: St. Mary's Hospital, London
• First patient treated with penicillin: Albert Alexander
• Date of first treatment: 12 February 1941

Last verified on 14-09-2026

Explanation

• A Barometer is an instrument used to measure air (atmospheric) pressure.
• It helps in weather forecasting by measuring changes in atmospheric pressure.
• The mercury barometer is the oldest type of barometer.
• It was invented by Evangelista Torricelli in 1643.
• Barometers are widely used in meteorology and aviation.

Last verified on 09-07-2026

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

• Ophthalmology is the study and medical specialty concerned with the eyes and vision.
• It deals with the structure, function, diseases, and treatment of the eyes.
• A doctor specializing in this field is called an ophthalmologist.
• Common eye conditions include cataracts, glaucoma, and refractive errors.

Last verified on 08-08-2026

Explanation

Antoine Henri Becquerel was an engineer, physicist, Nobel laureate,

First person to discover evidence of radioactivity.

 He belonged to France.

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

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

• Solar plates consist of photovoltaic (PV) cells.
• PV cells convert sunlight directly into electrical energy.
• These cells work on the photovoltaic effect. 
• They are usually made of semiconductor materials like silicon.

Additional information:

• Discovered photovoltaic effect: 1839 by Edmond Becquerel

Common types of solar cells:

1. Monocrystalline silicon cells
2. Polycrystalline silicon cells
3. Thin-film solar cells

Last verified on 23-06-2026

Explanation

• Lead pencil is made up of graphite.
• Graphite is a form (allotrope) of carbon.
• It is soft and leaves marks on paper easily.
• It is used in pencils because of its slippery layered structure.
• Despite the name “lead pencil,” it contains no real lead.
• Graphite was named by Abraham Gottlob Werner in 1789.

Last verified on 21-06-2026

Explanation

• Chronometer is a highly precise time-measuring instrument.
• It is often used in navigation and scientific experiments.
• It is designed to measure time accurately, even under varying conditions.
• Chronometers played a key role in determining longitude at sea.

Last verified on 03-04-2026