scientist, discoveries & inventions MCQ section 1 Practice Questions Answers Test with Solutions & More Shortcuts

Answer: (c)

The electron is a subatomic particle with a negative elementary electric charge. An electron has a mass that is approximately 1/1836 that of the proton.

The intrinsic angular momentum (spin) of the electron is a half-integer value in units of h, which means that it is a fermion. Like all matter, they have quantum mechanical properties of both particles and waves, so they can collide with other particles and can be diffracted like light.

The electron was identified as a particle in 1897 by J. J. Thomson and his team of British physicists.

Answer: (b)

Mosaic is the web browser credited with popularizing the World Wide Web. Marc Andreessen is best known as the co-author of Mosaic, the first widely used Web browser.

He is one of only six inductees in the World Wide Web Hall of Fame announced at the first international conference on the World Wide Web in 1994.

Answer: (c)

An anemometer is a device used for measuring the speed of wind. Anemometers are important tools for meteorologists, who study weather patterns. They are also important to the work of physicists, who study the way air moves.

Answer: (b)

King Camp Gillette, an American businessman, invented the best selling version of the safety razor in 1901. Several models were in existence before Gillette’s design.

Gillette’s innovation was the thin, inexpensive, disposable blade of stamped steel. Gillette is widely credited with inventing the so-called razor and blades business model.

Answer: (d)

Lactometer is used for measuring the density (creaminess) of milk. It is essentially a hydrometer which is an instrument used to measure the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water.