General Knowledge

Everyday Science and Technology

Chapter: Science & Technology

Question 1 of 5 NDA MCQ

 Which one of the following statements withrespect to Global Positioning System (GPS) isnot correct?

Detailed Explanation

Correct Answer

โœ“ Option D is correct. GPS provides information for civilian and commercial use, not exclusively military operations.

๐Ÿ“– 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.

๐Ÿ“œ 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.

๐Ÿ” 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.

โšก Chronology Trick / Polity Mnemonic

Remember the mnemonic "SAT-LOC" for GPS functioning: Satellites, Accuracy, Triangulation, Latitude, Optimized, Coordinates.

๐Ÿ“– Factual Verification & Reference

๐Ÿ“– Factual Verification & Reference:

Verified against "Fundamentals of GPS Technology," 5th Edition.

Question 2 of 5 NDA MCQ

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 ?

Detailed Explanation

Correct Answer

โœ“ Option (d) is correct. All statements about the Richter scale are accurate.

๐Ÿ“– 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.

๐Ÿงช 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.

๐Ÿ” Option Analysis

Each of the other options describes either incomplete or incorrect attributes of the Richter scale, making them less accurate than option (d).

โšก Mnemonic / Speed-Run

Remember: Richter scale, Energy release, No upper limit - R.E.N..

๐Ÿ“– Factual Verification & Reference

๐Ÿ“– Factual Verification & Reference:

Verified against "Seismology and Plate Tectonics" by the National Research Council.

Question 3 of 5 NDA MCQ

Which one of the following minerals is used as a fuel in nuclear power stations ?

Detailed Explanation

Correct Answer

โœ“ Option (d) is correct. Pitchblende is a primary ore of uranium, utilized as fuel in nuclear reactors.

๐Ÿ“– Governing Law / Core Concept

The mineral pitchblende, primarily composed of uranium dioxide (UOโ‚‚), is crucial for nuclear fission processes in power generation.

๐Ÿงช Step-by-Step Breakdown

Pitchblende contains uranium, which undergoes fission reactions, releasing large amounts of energy:

\[ \text{Uranium-235} \xrightarrow{\text{neutron}} \text{Fission Products} + \text{Energy} \]

This reaction generates heat that is used to produce steam and drive turbines in nuclear power stations.

๐Ÿ” 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.

โšก Mnemonic / Speed-Run

Remember: "Powerful Pitch" - Pitchblende is the source of power in nuclear energy.

๐Ÿ“– Factual Verification & Reference

๐Ÿ“– Factual Verification & Reference:

Verified against NCERT Class 12 Physics, Chapter on Nuclei and Radioactivity.

Question 4 of 5 NDA MCQ

To protect steel and iron from rusting, a thin layer of which one of the following metals is applied?

Detailed Explanation

Correct Answer

โœ“ Option B is correct. Zinc is used as a protective coating against rusting.

๐Ÿ“– Core Anchor Concept

Zinc is applied as a protective coating to iron and steel to prevent rusting (oxidation). This process is known as galvanization.

๐Ÿ“œ 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.

๐Ÿ” 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.

โšก Mnemonic / Speed-Run

MAG (Magnesium, Aluminium, Galvanization) - Remember that zinc (as in galvanization) is the go-to for rust prevention.

๐Ÿ“– Factual Verification & Reference

๐Ÿ“– Factual Verification & Reference:

Verified against NCERT Class 10 Science, Chapter on Metals and Non-Metals.

Question 5 of 5 NDA MCQ

Which one of the following is not a bio-mass energy source?

Detailed Explanation

Correct Answer

โœ“ Option (B) is correct. Nuclear reactors do not derive energy from organic matter.

๐Ÿ“– 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.

๐Ÿ“œ 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.

๐Ÿ” 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.

โšก Chronology Trick / Polity Mnemonic

Recall biomass energy sources with **"WGC"** (Wood, Gobar gas, Coal) as sustainable, while โ€œNโ€ (Nuclear reactor) stands apart as non-biological.

๐Ÿ“– Factual Verification & Reference

๐Ÿ“– Factual Verification & Reference:

Verified against standard sources on renewable energy and biomass concepts.

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