Railway Science (Physics-Discoveries)

Total Questions: 19

11. Who among the following developed the first prototype of electron microscope? [RRB JE 27/06/2019 (Evening)]

Correct Answer: (d) Ernst Ruska
Solution:

Ernst Ruska and Man Knoll (in 1931). Anton van Leeuwenhoek is acknowledged as the father of microbiology. He discovered protozoa, red blood cells. Robert Hooke discovery of the law of elasticity (Hooke’s law) and for his first use of the word “cell”. Theodor Schwann is considered a founder of cell theory.

12. Which of the following scientists showed that matter can be converted into energy and energy into matter ? [RRB Group D 03/10/2018 (Evening)]

Correct Answer: (b) Albert Einstein
Solution:

He stated that matter can be converted into energy, and developed a relation, E = mc² .

13. Who laid the foundation for the future development of radio, telephone, telegraph and television? [RRB Group D 03/10/2018 (Evening)]

Correct Answer: (b) Heinrich Rudolf Hertz
Solution:

The SI unit of frequency was named as 'hertz' in his honour. He is also credited with proving the existence of electromagnetic waves.

14. Who unified electricity, magnetism and optics, and showed that light is an electromagnetic wave? [RRB Group D 05/10/2018 (Morning)]

Correct Answer: (c) James Maxwell
Solution:

Isaac Newton - Best known for laws of motion and his theory of universal gravitation. Carlo Rubbia (In 1984 - Nobel Prize in Physics) - Known for his work on the discovery of the W and Z bosons, which are fundamental particles that mediate the weak force. Sheldon Glashow (In 1979 - Nobel Prize in Physics) - Known for his efforts in formulating the electroweak theory, which explains the unity of electromagnetism and the weak force.

15. Alternating current was invented by _______. [RRB Group D 09/10/2018 (Morning)]

Correct Answer: (a) Nikola Tesla
Solution:

Famous scientists and discoveries: Albert Einstein was best known for his General and Special theory of relativity and the concept of mass-energy equivalence (E = mc²). Thomas Edison - Light Bulb, Phonograph. Isaac Newton - laws of gravity. J.J Thomson - Electron. Ernest Rutherford - Proton. John Dalton - Theory on atoms.

16. What was the year of publication of Newton's laws of motion? [RRB Group D 27/11/2018 (Evening)]

Correct Answer: (d) 1687
Solution:

Newton's Laws of Motion are three physical laws which provide relationships between the forces acting on a body and the motion of the body, first formulated by Sir Isaac Newton. Newton's laws were first published in his work “Philosophiae Naturalis Principia Mathematica”.

17. _______ argued that all the planets orbit the Sun, not the Earth, contrary to the belief of the time. [RRB Group D 14/12/2018 (Afternoon)]

Correct Answer: (b) Galileo Galilei
Solution:

He was an Italian astronomer and physicist who supported the heliocentric model of Copernicus, which stated that the Earth and other planets revolve around the Sun.

18. Which of the following branches of mathematics was invented by Newton? [RRB ALP Tier - I (10/08/2018) Afternoon]

Correct Answer: (a) Calculus
Solution:

It was invented by Isaac Newton in 1665. Euclid (mathematician) is often called the father of geometry. Algebra - It was discovered by Muhammad ibn Musa al-Khwarizmi.

19. The quantum theory of light was given by: [RRB ALP Tier - I (20/08/2018) Afternoon]

Correct Answer: (d) Plank
Solution:

According to Planck’s quantum theory, different atoms and molecules can emit or absorb energy in discrete quantities only. Planck has also concluded that these were only an aspect of the processes of absorption and emission of radiation, Later in 1905, German physicist Albert Einstein also reinterpreted Planck’s theory to further explain the photoelectric effect (when light shone onto a metal surface causes the ejection of electrons from that metal), E = h ν where, E = Energy of the radiation, h = Planck’s constant (6.626 × 10⁻³⁴ J.s), ν = Frequency of radiation.