SENAPREP
Achievements of Eminent Scientists Questions
Chapter: Science & Technology | Total Available: 20 Real Questions
Which one of the following statements withrespect to Global Positioning System (GPS) isnot correct?
Correct Answer
📖 Core Anchor Concept
The Global Positioning System (GPS) is a satellite-based navigation system used for location determination, which relies on a network of satellites circling the Earth.
📜 Detailed Breakdown & Chronology
- Satellite Network: GPS comprises at least 24 satellites, allowing triangulation to determine geographic location.
- Triangulation: The system utilizes three or more satellites to calculate a precise location through distance measurement.
- Positioning Data: GPS provides coordinates in latitude, longitude, and altitude, enhancing map accuracy.
- Wide Use: Originally developed for military purposes, GPS technology has expanded into civilian applications, serving various sectors including traffic navigation and scientific research.
🔍 Option Analysis
- Option A: Correct, as GPS is based on a network of satellites.
- Option B: Correct, since GPS operates using triangulation methods.
- Option C: Correct, GPS receivers do provide location data as mentioned.
- Option D: Incorrect, as GPS is not exclusive to military use; it encompasses civilian applications widely.
⚡ Chronology Trick / Polity Mnemonic
Remember the mnemonic "SAT-LOC" for GPS functioning: Satellites, Accuracy, Triangulation, Latitude, Optimized, Coordinates.
📖 Factual Verification & Reference
Verified against "Fundamentals of GPS Technology," 5th Edition.
SONAR stands for
Correct Answer
📖 Core Anchor Concept
SONAR is a technology that uses sound propagation to navigate, communicate with, or detect objects on or under the surface of the water.
📜 Detailed Breakdown & Chronology
- Sound Waves: SONAR sends sound waves that bounce off objects, allowing for their detection.
- Types: Active SONAR transmits sound pulses; passive SONAR listens for sounds.
- Applications: Primarily used in marine navigation, submarines, and fishing.
🔍 Option Analysis
- A: Sonographic Natural Ranging - incorrect and does not relate to sound.
- B: Simple Operational Navigation Ranging - misleading as it misrepresents the function.
- D: Simple Operational Natural Ranging - doesn't accurately depict the technology.
⚡ Chronology Trick / Polity Mnemonic
Remember: SONAR = Sound + Navigation + Ranging. The acronym reflects its primary function of using sound for navigation and object detection.
📖 Factual Verification & Reference
Verified against standard marine navigation textbooks and technical glossaries.
LED (a semi-conductor device) is an abbreviation that stands for
Correct Answer
📖 Core Anchor Concept
LED (Light Emitting Diode) is a semiconductor device that emits light when an electric current passes through it. This happens due to the recombination of electrons and holes in the diode's p-n junction.
📜 Detailed Breakdown & Chronology
The operation principle of an LED involves:
- When an LED is forward-biased, electrons move from the n-type material to the p-type material.
- Recombination of electrons with holes results in energy being released in the form of photons (light).
This phenomenon adheres to the principles of electroluminescence, first observed in 1907 by H. J. Round.
🔍 Option Analysis
Reasons other options are incorrect:
- A: Licence for Energy Detector - This is not a recognized term in electronics.
- B: Light Energy Device - This does not accurately describe how LEDs function.
- D: Lost Energy Detector - This is misleading and does not relate to LED technology.
⚡ Mnemonic / Speed-Run
Mnemonic to remember LED:
Light Emitting Diode = Light generated by electricity!
📖 Factual Verification & Reference
Verified against standard electronics and physics textbooks.
Which one of the following is not a bio-mass energy source?
Correct Answer
📖 Core Anchor Concept
Biomass energy comes from organic materials, such as plant and animal waste, which can be renewed sustainably. This includes resources like wood, coal, and gobar gas.📜 Detailed Breakdown & Chronology
- **Biomass**: Sources (e.g., wood, coal, gobar gas) are derived from biological matter. They release energy upon combustion or decomposition. - **Nuclear Energy**: Generated via fission or fusion processes in atoms, primarily uranium or thorium. It is non-renewable and does not originate from biological processes, hence not a biomass energy source.🔍 Option Analysis
- **A: Wood**: A traditional biomass source, burned for heat. - **B: Nuclear reactor**: Generates energy through nuclear reactions, not organic matter. - **C: Gobar gas**: Biogas produced from organic waste, a renewable energy source. - **D: Coal**: A fossilized biomass, once organic matter, but with environmental concerns.⚡ Chronology Trick / Polity Mnemonic
Recall biomass energy sources with **"WGC"** (Wood, Gobar gas, Coal) as sustainable, while “N” (Nuclear reactor) stands apart as non-biological.📖 Factual Verification & Reference
Verified against standard sources on renewable energy and biomass concepts.
To protect steel and iron from rusting, a thin layer of which one of the following metals is applied?
Correct Answer
📖 Core Anchor Concept
Zinc is applied as a protective coating to iron and steel to prevent rusting (oxidation). This process is known as galvanization.
📜 Detailed Breakdown & Chronology
Rusting is an electrochemical process where iron reacts with moisture and oxygen to form iron oxide. Galvanization, using zinc which is more reactive than iron, effectively shields iron by corroding preferentially.
Process Overview:
- Electroplating setup is formed with iron as the cathode and zinc as the anode.
- During electrolysis, zinc ions migrate to the iron surface, forming a protective layer, thus delaying rusting.
🔍 Option Analysis
- A: Magnesium - Not commonly used; less effective in rust prevention.
- C: Aluminium - Forms a protective oxide layer but is less common than zinc for rust prevention.
- D: Lead - Toxic and impractical for such applications; does not effectively prevent rust.
⚡ Mnemonic / Speed-Run
MAG (Magnesium, Aluminium, Galvanization) - Remember that zinc (as in galvanization) is the go-to for rust prevention.
📖 Factual Verification & Reference
Verified against NCERT Class 10 Science, Chapter on Metals and Non-Metals.
Which one of the following minerals is used as a fuel in nuclear power stations ?
Correct Answer
📖 Governing Law / Core Concept
The mineral pitchblende, primarily composed of uranium dioxide (UO₂), is crucial for nuclear fission processes in power generation.
🧪 Step-by-Step Breakdown
Pitchblende contains uranium, which undergoes fission reactions, releasing large amounts of energy:
This reaction generates heat that is used to produce steam and drive turbines in nuclear power stations.
🔍 Option Analysis
- A: Bauxite - An ore of aluminum, not used in nuclear reactors.
- B: Quartz - Mainly composed of silica, used in electronics, not as nuclear fuel.
- C: Feldspar - Used in ceramics and glass, irrelevant for nuclear energy.
⚡ Mnemonic / Speed-Run
Remember: "Powerful Pitch" - Pitchblende is the source of power in nuclear energy.
📖 Factual Verification & Reference
Verified against NCERT Class 12 Physics, Chapter on Nuclei and Radioactivity.
Who among the following has explained the phenomenon of photoelectric effect ?
Correct Answer
📖 Governing Law / Core Concept
The photoelectric effect can be explained by Einstein's equation:
where \( E \) is the energy of emitted photoelectrons, \( h \) is Planck's constant, \( f \) is the frequency of incident light, and \( \phi \) is the work function.
🧪 Step-by-Step Breakdown
The photoelectric effect refers to the emission of electrons from a material when it absorbs light. The key steps include:
- The absorption of photons by electrons in a material.
- The conversion of photon energy to kinetic energy of the ejected electrons.
- Threshold frequency must be met for emission to occur, indicated by the work function.
🔍 Option Analysis
- A. Max Planck: Proposed quantization of energy but did not explain the photoelectric effect.
- C. Neils Bohr: Developed the model of the atom, focusing on electron orbits but not specifically on the photoelectric phenomenon.
- D. Ernest Rutherford: Known for the nuclear model of the atom but unrelated to the photoelectric effect.
⚡ Mnemonic / Speed-Run
Remember Einstein’s contribution with the phrase: “Energy from light knocks out electrons” to recall the essence of the photoelectric effect.
📖 Factual Verification & Reference
Verified against NCERT Class XII Physics, Chapter 11 (Dual Nature of Radiation and Matter).
Consider the following statements relating to Richter scale :
(1) It was devised in 1935 by Charles F. Richter .
(2) It describes the quantity of energy released by a single earthquake .
(3) Richter Scale has no upper limit Which of the statements given above is/are correct ?
Correct Answer
📖 Governing Law / Core Concept
The Richter scale, developed by Charles F. Richter in 1935, quantifies the magnitude of seismic energy released by earthquakes on a logarithmic scale.
🧪 Step-by-Step Breakdown
- (1) Established in 1935 by Charles F. Richter.
- (2) Measures the energy released from a single earthquake event.
- (3) There is no upper limit on the Richter scale, meaning magnitudes can theoretically progress indefinitely.
🔍 Option Analysis
Each of the other options describes either incomplete or incorrect attributes of the Richter scale, making them less accurate than option (d).
⚡ Mnemonic / Speed-Run
Remember: Richter scale, Energy release, No upper limit - R.E.N..
📖 Factual Verification & Reference
Verified against "Seismology and Plate Tectonics" by the National Research Council.
LIGO stands for
Correct Answer
📖 Governing Law / Core Concept
LIGO employs laser interferometry to measure disturbances caused by gravitational waves, enabling the detection of cosmic events like black hole mergers.
🧪 Step-by-Step Breakdown
The term encapsulates the following key components:
- Laser: Refers to the light source used for measuring.
- Interferometer: The device that uses the interference of light beams to measure minute changes in distance.
- Gravitational-wave: Ripples in spacetime produced by accelerating massive objects.
- Observatory: A facility designed for research and observation of cosmic phenomena.
🔍 Option Analysis
Other options are incorrect due to the following reasons:
- B: "Light" is inaccurately replacing "Laser".
- C: Misleading terminology as gravity is not directly implied.
- D: Incorrect as it doesn't relate to gravitational waves.
⚡ Mnemonic / Speed-Run
Remember "LIGO" as: Light, Interferometer, Gravitational, Observatory.
📖 Factual Verification & Reference
Verified against scientific literature, "The Detection of Gravitational Waves: LIGO and the Supernova Neutrino", Springer.
Initial discovery of antibiotic penicillin was done by
1. Correct Answer
Option D is correct. Alexander Fleming discovered penicillin in 1928.
📖 Core Concept
Penicillin, the first true antibiotic, was discovered by Alexander Fleming when he observed its effects on bacteria, leading to a revolutionary change in medicine.
💡 3. Explanation
❌ 4. Option Analysis
- • Option A: Francis Crick was a molecular biologist famous for discovering the structure of DNA, not penicillin.
- • Option B: Maurice Wilkins was a physicist and later a molecular biologist known for his work on DNA, but he did not discover penicillin.
- • Option C: Charles Darwin was a naturalist renowned for his theory of evolution, with no relation to antibiotic discovery.
NDA Speed-Run / Mnemonic Shortcut
Remember: "Fleming Found Fungus" to recall that Alexander Fleming discovered penicillin from the Penicillium mold.
5. Key Takeaways
Alexander Fleming is credited with the discovery of penicillin, which initiated the antibiotic revolution.