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

Answer: (c)

Answer: (c)

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)

The smallpox vaccine was the first successful vaccine to be developed. The process of vaccination was first publicised by Edward Jenner in 1796, who acted upon his observation that milkmaids who caught the cowpox virus did not catch smallpox.

Before the introduction of a vaccine, the mortality of the severe form of smallpox—variola major—was very high. Historical records show that a method of inducing immunity was already known.

A process called inoculation, also known as insufflation or variolation was practised in India as early as 1000 BC.

Answer: (d)

An automobile is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor.

The term motorcar has also been used in the context of electrified rail systems to denote a car that functions as a small locomotive but also provides space for passengers and baggage.

Although several other German engineers (including Gottlieb Daimler, Wilhelm Maybach, and Siegfried Marcus) were working on the problem at about the same time, Karl Benz generally is acknowledged as the inventor of the modern automobile.

Answer: (d)