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

Answer: (d)

Answer: (c)

When Card David Anderson discovered a new particle with a mass between that of the electron and proton, he named it 'mesoton' in a 1933 publication in the Physical Review.

However, on the advice of Professor R.A. Millikan, he changed the name to ‘mesotron’ although he (Anderson) did not agree with it.

Homi Jehangir Bhabha then sent a short paper to Nature journal in February 1939 in which he proposed the name meson. The name given by Bhabha has remained to this day and is used for a class of elementary particles.

Answer: (b)

The instrument used to measure electrical current is called an ammeter, which is actually a shortened form of ‘amp meter’. The current is measured in amperes. In scientific labs, a much more sensitive instrument called a galvanometer is used to measure very small currents.

Answer: (b)

World Wide Web (www) was invented by English scientist Tim Berners-Lee in 1989. It is an information space where documents and other web resources are identified by URLs, interlinked by hypertext links, and can be accessed via the Internet.

Answer: (d)

A videotape is a recording of images and sounds onto magnetic tape as opposed to film stock used in filmmaking or random access digital media. Videotapes are also used for storing scientific or medical data, such as the data produced by an electrocardiogram.

Charles P. Ginsburg invented the videotape. He worked for Ampex and was inspired by the reel-to-reel machines used for recording sound.

Answer: (b)

Gunpowder was the first chemical explosive and the only one known until the invention of nitrocellulose, nitroglycerin, smokeless powder, and TNT in the second half of the 19th century.

Prior to the invention of gunpowder, many incendiary and burning devices had been used, including Greek fire. Roger Bacon invented gunpowder.