scientist, discoveries & inventions MCQ section 4 MCQ Questions & Answers Detailed Explanation

Answer: (a)

Martin Cooper, an American engineer, conceived the first handheld mobile phone while at Motorola in 1973. He led the team that developed it and brought it to market in 1983. He is considered the “father of the cell phone” and is also cited as the first person in history to make a handheld cellular phone call in public.

Answer: (d)

Meteorology is the scientific study of the atmosphere or weather. Meteorological phenomena are observable weather events which are explained by the science of meteorology. Those events are bound by the variables that exist in Earth’s atmosphere; temperature, air pressure, water vapor, etc.

Answer: (d)

Dr Hans von Ohain and Sir Frank Whittle are both recognized as being the co-inventors of the jet engine. Each worked separately and knew nothing of the other’s work. Hans von Ohain is considered the designer of the first operational turbojet engine.

Frank Whittle was the first to register a patent for the turbojet engine in 1930. Hans von Ohain was granted a patent for his turbojet engine in 1936. However, Hans von Ohain’s jet was the first to fly in 1939. Frank Whittle’s jet first flew in 1941.

Answer: (a)

In physics, cryogenics is the study of the production and behaviour of materials at very low temperatures.

It is not well-defined at what point on the temperature scale refrigeration ends and cryogenics begins, but scientists assume it starts at or below - 150°C (123 K; -238 °F).

Answer: (d)

X-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×1016 Hz to 3×1019 Hz) and energies in the range 100 eV to 100 keV.

They are shorter in wavelength than UV rays and longer than gamma rays.

In many languages, X-radiation is called Röntgen radiation, after Wilhelm Röntgen, who is usually credited as its discoverer, and who had named it X-radiation to signify an unknown type of radiation.

Answer: (c)