scientist, discoveries & inventions MCQ section 2 Practice Questions Answers Test with Solutions & More Shortcuts

Answer: (d)

Attempts to create helicopters can be traced back to Leonardo da Vinci, but the first working prototype helicopter, the VS-300, was invented by Igor Sikorsky in 1939.

The next model he designed was the R4 in 1942, which was the world’s first mass-produced helicopter.

Answer: (c)

In electronics, a vacuum tube, thermionic valve, tube, or valve is a device controlling electric current through a vacuum in a sealed container. The container is often thin transparent glass in a roughly cylindrical shape.

Sir John Ambrose Fleming (29 November 1849 – 18 April 1945) was an English electrical engineer and physicist. He is known for inventing the first thermionic valve or vacuum tube, the diode, then called the kenotron in 1904. He is also famous for the left-hand rule (for electric motors).

Answer: (d)

Scientists are able to understand Earth’s interior with the help of seismology. Seismology involves the study of seismic waves that travel through Earth. Seismic waves are sent through the earth during earthquakes.

In contrast, Plate Tectonics is the study of the movement of the Earth’s crust due mainly to forces in the crust and upper mantle of the Earth’s interior.

Answer: (b)

The discovery of penicillin is attributed to Scottish scientist and Nobel laureate Alexander Fleming in 1928.

Penicillin is a secondary metabolite of certain species of Penicillium and is produced when the growth of the fungus is inhibited by stress. It is not produced during active growth.

Answer: (c)