Explanation

• Marconi invented Radio.
• Radio was invented in 1895.
• Guglielmo Marconi was an Italian inventor.

Last verified on 12-08-2026

Explanation

• Inventor: Thomas Alva Edison.
• Country: United States.
• Practical incandescent bulb: 1879.
• Other contributions: Electric power, sound recording, motion pictures.
• Famous invention: Phonograph.

Last verified on 03-09-2026

Explanation

• The Doppler Effect is the change in the observed frequency of sound due to the relative motion between the source and the observer.
• If the source and observer move toward each other, the observed frequency increases.
• If they move away from each other, the observed frequency decreases.
• A common example is the changing pitch of an ambulance siren as it passes by.

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

• Pressure is a scalar quantity.
• Pressure can be defined as the force acting per unit area.
• The unit of pressure is N/m² (Newton per square meter).
• It is also called a pascal (Pa).
• In SI base units: kg⋅m−1⋅s−2
• Derivation from other quantities: p = F / A
• Dimensional unit: M L^−1 T^-2.