PREVIOUS YEAR QUESTIONS
Q.1) Electrically charged particles form space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth? (2012)
A. The Earth’s magnetic field diverts them towards its poles.
B. Ozone layer around the Earth reflects them back to outer space.
C. Moisture in the upper layers of atmosphere prevents them from reaching the surface of the Earth.
D. None of the statements (a), (b) and (c) given above is correct
Answer: A
Explanation:
- The Earth’s magnetic field plays a crucial role in protecting the planet from the harmful effects of electrically charged particles from space, such as solar wind and cosmic rays. These charged particles, mainly protons and electrons, are constantly streaming from the Sun at speeds of several hundred kilometers per second.
- When these charged particles approach the Earth, the planet’s magnetic field acts as a protective shield. The Earth’s magnetic field is generated by the movement of molten iron and nickel in its outer core, creating a complex magnetic field that extends into space. This magnetic field creates a region around the Earth known as the magnetosphere.
- As charged particles from the Sun encounter the Earth’s magnetosphere, they experience the magnetic force. This force causes the charged particles to be deflected and redirected around the Earth rather than penetrating the atmosphere and reaching the surface. The magnetic field lines guide these particles toward the polar regions, where they interact with the Earth’s atmosphere, creating phenomena like the auroras (Northern and Southern Lights).
Q.2) What is ‘Greased Lightning-10 (GL-10). recently in the news? (2016)
A. Electric plane tested by NASA
B. Solar-powered two-seater aircraft designed by Japan
C. Space observatory launched by China
D. Reusable rocket designed by ISRO
Answer: A
Explanation:
- Greased Lightning-10 (GL-10) is an electric aircraft that has been tested by NASA. It is a vertical takeoff and landing (VTOL) vehicle, demonstrating innovative electric propulsion technology. The aircraft is part of NASA’s efforts to explore and develop new technologies for more efficient and environmentally friendly air transportation.
Q.3) Consider the following statements:The Mangalyaan launched by ISRO (2016)
- is also called the Mars Orbiter Mission
- made India the second country to have a spacecraft orbit the Mars after USA
- made India the only country to be successful in making its spacecraft orbit the Mars in its very first attempt
Which of the statements given above is/are correct?
A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3
Answer: C
Explanation:
- Mangalyaan is also called the Mars Orbiter Mission: This statement is correct. The Mars Orbiter Mission, launched by ISRO, is often referred to as Mangalyaan. It was launched on November 5, 2013.
- Mangalyaan made India the second country to have a spacecraft orbit Mars after the USA: This statement is incorrect. In fact, Mangalyaan made India the first Asian country and the first country in the world to successfully reach Mars orbit in its maiden attempt. It achieved this milestone on September 24, 2014.
- Mangalyaan made India the only country to be successful in making its spacecraft orbit Mars in its very first attempt: This statement is correct. India, through the Mars Orbiter Mission, became the only country to successfully enter Mars orbit on its inaugural attempt.
- Launch details:
- Launch Year: 2013
- Launch Vehicle: Mangalyaan was launched aboard a Polar Satellite Launch Vehicle (PSLV-C25) on November 5, 2013, from the Satish Dhawan Space Centre in Sriharikota, India.
Q.4) With reference to ‘Astrosat, the astronomical observatory launched by India, which of the following statements is/are correct? (2016)
- Other than USA and Russia, India is the only country to have launched a similar observatory into space.
- Astrosat is a 2000 kg satellite placed in an orbit at 1650 km above the surface of the Earth.
Select the correct answer using the code given below.
A. 1 only
B. 2 only
C. Both 1 and 2
D. Neither 1 nor 2
Answer: D
Explanation:
- Objective: Astrosat is designed to observe celestial objects in different wavelengths, including ultraviolet, optical, and X-rays. It aims to study a wide range of astronomical phenomena, such as stars, galaxies, and other celestial bodies.
- Payloads: Astrosat carries five scientific instruments on board, each dedicated to specific wavelength bands. The instruments include the Ultraviolet Imaging Telescope (UVIT), the Soft X-ray Telescope (SXT), the Large Area Xenon Proportional Counter (LAXPC), the Cadmium Zinc Telluride Imager (CZTI), and the Charge-Coupled Device (CCD) camera.
- Mass: The satellite has a mass of approximately 1513 kg.
- Orbit: Astrosat operates in a near-equatorial, low Earth orbit (LEO) at an altitude of approximately 650 km.
- International Collaboration: Astrosat has international collaboration, and some of its instruments are provided by other countries, including the UVIT instrument, which is a result of collaboration with Canada and the Netherlands.
- Observations: Astrosat has made significant contributions to the field of astronomy by providing valuable data on a variety of celestial objects, contributing to our understanding of the universe.
- Other than USA and Russia, India is the only country to have launched a similar observatory into space: This statement is incorrect. While India’s Astrosat is a significant achievement, other countries, including European Space Agency (ESA) member countries, have also launched similar astronomical observatories into space.
Q.3) The terms Event Horizon’, ‘Singularity’, ‘String Theory’ and ‘Standard Model’ are sometimes seen in the news in the context of (2017)
A. Observation and understanding of the Universe
B. Study of the solar and the lunar eclipses
C. Placing satellites in the orbit of the Earth
D. Origin and evolution of living organisms on the Earth
Answer: A
Explanation:
- Event Horizon: The event horizon is a boundary in spacetime beyond which events cannot affect an observer. In the context of astrophysics and black holes, it refers to the boundary around a black hole where the gravitational pull is so strong that nothing, not even light, can escape.
- Singularity: In astrophysics and general relativity, a singularity is a point in spacetime where the gravitational field becomes infinitely strong, and the curvature of spacetime becomes infinite. Singularities are often associated with the center of black holes.
- String Theory: String theory is a theoretical framework in physics that attempts to explain the fundamental nature of particles and forces by modeling them as tiny, one-dimensional “strings” rather than point-like particles. It is a candidate for a theory of everything that unifies quantum mechanics and general relativity.
- Standard Model: The Standard Model of particle physics is a theory describing the electromagnetic, weak, and strong nuclear interactions, which are the basic forces that make up the universe. It includes elementary particles such as quarks, leptons, and gauge bosons. However, the Standard Model has limitations, and physicists are exploring beyond it in search of a more comprehensive theory.
Q.6) What is the purpose of ‘evolved Laser Interferometer Space Antenna (eLISA)” project? (2017)
A. To detect neutrinos
B. To detect gravitational waves
C. To detect the effectiveness of missile defence system
D. To study the effect of solar flares on our communication systems
Answer: B
Explanation:
- The ‘evolved Laser Interferometer Space Antenna (eLISA)’ is a project designed for the detection and study of gravitational waves. Gravitational waves are a prediction of Albert Einstein’s theory of general relativity. They are ripples in the fabric of spacetime caused by certain dynamic events in the universe, such as the acceleration of massive objects or the collision and merging of compact objects like black holes and neutron stars.
- Laser Interferometry: The fundamental principle behind eLISA involves using laser interferometry to detect gravitational waves. In a simplified sense, interferometry involves splitting a laser beam into two separate paths and then recombining them. Gravitational waves passing through spacetime cause a minute stretching and compressing of space, affecting the lengths of the laser arms. By measuring the interference pattern when the laser beams are recombined, scientists can detect these subtle changes in length caused by passing gravitational waves.
- Space-Based Observatory: eLISA is designed to be a space-based observatory, which is a crucial aspect of its design. Placing the detector in space eliminates many of the environmental disturbances and allows for larger baseline lengths, enhancing sensitivity to gravitational wave signals.
- Evolution of LISA: The term “evolved” in eLISA indicates the evolution of the concept from an earlier proposal known as LISA (Laser Interferometer Space Antenna). The evolution involves technological improvements and advancements in the design of the observatory.
- Detecting Cataclysmic Events: Gravitational waves carry information about the dynamics of cataclysmic events in the universe. By detecting and studying these waves, scientists can gain insights into phenomena such as the merger of supermassive black holes at the centers of galaxies, the collision of neutron stars, and other extreme astrophysical events.
- Global Collaboration: The eLISA project represents a collaboration between space agencies and scientific institutions from around the world, including the European Space Agency (ESA). The construction and operation of such advanced observatories require global cooperation to pool expertise and resources.
Q.7) In which of the following areas can GPS technology be used (2018)
- Mobile phone operations
- Banking operations
- Controlling the power grids
Select the correct answer using the code given below:
A. 1 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3
Answer: D
Explanation:
Mobile Phone Operations:
GPS technology plays a crucial role in mobile phone operations, providing various location-based services and functionalities:
- Navigation: GPS enables precise navigation on mobile devices. It helps users find directions, locate nearby points of interest, and plan routes.
- Location-Based Services: Many mobile applications utilize GPS to offer location-specific services, such as weather updates, local business information, and social networking features.
- Emergency Services: GPS is integral for emergency services to accurately locate individuals in distress when they make calls for assistance.
- Tracking and Security: GPS is employed for tracking devices, enhancing security features, and helping in the recovery of lost or stolen phones.
- Banking Operations:
- GPS technology can be applied in various ways within the banking sector to enhance services and security:
- Transaction Verification: For added security, banks may use GPS data to verify the location of a user when conducting certain transactions. This helps in detecting and preventing fraudulent activities.
- ATM Locator Services: Banks often utilize GPS to provide users with real-time information on the locations of ATMs or branch offices.
- Mobile Banking Security: GPS can contribute to securing mobile banking applications by confirming the user’s location during transactions, reducing the risk of unauthorized access.
- Controlling Power Grids:
- GPS technology has applications in power grid management, particularly for synchronization, timekeeping, and monitoring:
- Synchronization: Precise timing is crucial for the reliable operation of power grids. GPS provides accurate and synchronized time information to ensure the coordination of various elements within the grid.
- Fault Location and Monitoring: GPS aids in quickly identifying the location of faults or disruptions in the power grid, allowing for prompt response and restoration.
- Grid Monitoring: GPS can be used for real-time monitoring of the power grid, helping operators assess the health of the system and make informed decisions to optimize its performance.
Q.8) With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements: (2018)
- IRNSS has three satellites in geostationary and four satellites in geosynchronous orbits.
- IRNSS covers entire India and about 5500 sq. km beyond its borders.
- India will have its own satellite navigation system with full global coverage by the middle of 2019,
Which of the statements given above is/are correct?
A. 1 only
B. 1 and 2 only
C. 2 and 3 only
D. None
Answer: A
Explanation:
- The Indian Regional Navigation Satellite System (IRNSS), also known as NavIC (Navigation with Indian Constellation), is an independent regional navigation satellite system developed by the Indian Space Research Organisation (ISRO).
Objective:
- The primary objective of IRNSS is to provide accurate position information services to users in India and the surrounding region.
Number of Satellites:
- The IRNSS constellation comprises a total of seven satellites.
Orbit:
- All seven IRNSS satellites are placed in geosynchronous orbits. three satellites in geostationary and four satellites in geosynchronous orbits.
Coverage Area:
- IRNSS covers a region extending approximately 1,500 kilometers beyond India’s borders. The coverage area is designed to serve not only India but also neighboring countries.
Signal Frequencies:
- IRNSS uses two types of signals for navigation purposes: Standard Positioning Service (SPS) and Restricted Service (RS). The SPS is meant for civilian use, while the RS is an encrypted service designed for authorized users.
Applications:
- IRNSS is utilized for a variety of applications, including terrestrial, aerial, and marine navigation, disaster management, vehicle tracking, and precise timing information.
Satellite Names:
- The seven satellites in the IRNSS constellation are named as IRNSS-1A, IRNSS-1B, IRNSS-1C, IRNSS-1D, IRNSS-1E, IRNSS-1F, and IRNSS-1G.
Integration with Other Navigation Systems:
- While IRNSS is primarily a regional system, efforts are being made to integrate it with other global navigation satellite systems (GNSS) to enhance its accuracy and provide global coverage.
Expansion to Global Coverage:
- India has plans to expand the capabilities of its navigation system to achieve global coverage. As of now IRNSS is evolving, and ISRO continues to work towards integrating it with other systems for broader global navigation coverage.
Q.9) Consider the following phenomena: (2018)
- Light is affected by gravity.
- The Universe is constantly expanding.
- Matter wrap its surrounding space-time.
Which of the above is/are the prediction/ predictions of Albert Einstein’s General Theory of Relativity, often discussed in media”
A. 1 and 2 only
B. 3 only
C. 1 and 3 only
D. 1, 2 and 3
Answer: D
Explanation:
- Albert Einstein’s General Theory of Relativity, formulated between 1907 and 1915, revolutionized our understanding of gravity and the fabric of spacetime.
Curvature of Spacetime:
- Concept: In classical physics, gravity was viewed as a force between masses. Einstein, however, proposed a radical shift in perspective. He argued that massive objects, such as planets or stars, don’t exert a force directly but instead warp the fabric of spacetime around them.
- Prediction: The curvature of spacetime causes objects to move on curved paths, and this is what we perceive as gravity. The more massive an object, the more it warps spacetime, affecting the motion of nearby objects.
- Equivalence Principle:
- Concept: Einstein’s theory introduced the equivalence principle, stating that in a small enough region of spacetime, the effects of gravity are indistinguishable from acceleration.
- Prediction: This principle implies that objects in free fall experience gravity in the same way they would experience inertial motion in the absence of gravity. It led to the idea that gravitational mass and inertial mass are equivalent.
- Gravitational Time Dilation:
- Concept: According to general relativity, time is relative and can be affected by gravity. Clocks in stronger gravitational fields tick more slowly.
- Prediction: This phenomenon is known as gravitational time dilation. For example, a clock closer to a massive object like Earth ticks more slowly than a clock farther away in space.
- Gravitational Lensing:
- Concept: Massive objects, like stars or galaxies, can bend the path of light passing near them due to the curvature of spacetime.
- Prediction: This gravitational lensing effect was confirmed through observations, such as the bending of starlight during a solar eclipse. It has become a crucial tool for studying distant objects in the universe.
- Expanding Universe:
- Concept: Einstein initially introduced a cosmological constant to maintain a static universe, as it was believed to be at the time.
- Observational Evidence: Edwin Hubble’s observations revealed that galaxies are moving away from each other, indicating an expanding universe. Einstein’s equations could describe an expanding universe without the cosmological constant, leading to the model of an evolving cosmos.
- Gravitational Waves:
- Concept: Einstein’s equations predicted the existence of gravitational waves—ripples in spacetime caused by accelerating masses.
- Observational Confirmation: In 2015, the LIGO experiment detected gravitational waves for the first time, providing direct experimental evidence for this prediction.
Q.10) With reference to India’s satellite launch vehicles, consider the following statements: (2018)
- PSLVs launch the satellites useful for Earth resources monitoring whereas GSLVs are designed to launch communication satellites
- Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth.
- GSLV Mk III is a four-staged launch vehicle with the first and third stages using solid rocket motors; and the second and fourth stages using liquid rocket engines.
Which of the statements given above is/are correct?
A. 1 only
B. 2 and 3 only
C. 1 and 2 only
D. 3 only
Answer: A
Explanation:
Polar Satellite Launch Vehicle (PSLV):
Generation and Role:
- PSLV is a third-generation launch vehicle developed by ISRO.
- It is known as the “Workhorse of ISRO” due to its consistent performance in delivering various satellites to Low Earth Orbits (LEO).
Configuration:
- PSLV is a four-stage launch vehicle.
- The second and fourth stages use liquid rocket engines, while the first and third stages use solid rocket motors.
Payload Capacity and Purpose:
- PSLV is designed to deliver Earth-observation or remote-sensing satellites.
- It can handle lift-off masses of up to about 1750 Kg.
Orbit Capability:
- PSLV is capable of delivering satellites to Sun-Synchronous circular polar orbits with altitudes ranging from 600 to 900 Km.
Geosynchronous Satellite Launch Vehicle (GSLV):
Development and Design:
- GSLV is developed, designed, and operated by ISRO.
- GSLV Mk III is a version of GSLV, specifically designed for heavy lift capabilities.
Configuration:
- GSLV Mk III is a three-stage heavy lift launch vehicle.
- It consists of two solid strap-on boosters, a core liquid booster, and a cryogenic upper stage.
Payload Capacity and Purpose:
- GSLV Mk III is designed to carry four-ton class satellites into Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO).
- The primary purpose of GSLV is to deliver communication satellites.
Geosynchronous Orbits:
- Due to their geosynchronous nature, satellites launched by GSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth.
Q.11) For the measurement/estimation of which of the following are satellite images/remote sensing data used? (2019)
- Chlorophyll content in the vegetation of a specific location
- Greenhouse gas emissions from rice paddies of a specific location
- Land surface temperatures of a specific location
Select the correct answer using the code given below.
A. 1 only
B. 2 and 3 only
C. only
D. 1, 2 and 3
Answer: D
Explanation:
Chlorophyll content in the vegetation of a specific location:
- Satellite images and remote sensing data can be used to estimate chlorophyll content in vegetation. This is typically done through the analysis of spectral reflectance in different bands, as chlorophyll has distinct absorption features in certain wavelengths. Therefore, Statement 1 is correct.
Greenhouse gas emissions from rice paddies of a specific location:
- Satellite data can be used to estimate greenhouse gas emissions from rice paddies by monitoring land use changes, vegetation health, and other relevant factors. For example, remote sensing can help identify flooded rice fields, a key factor in methane emissions. Therefore, Statement 2 is correct.
Land surface temperatures of a specific location:
- Satellite images and remote sensing data can provide information about land surface temperatures by capturing thermal infrared radiation. This is valuable for various applications, including climate studies, urban heat island monitoring, and agricultural assessments. Therefore, Statement 3 is correct.
Q.12) Recently, scientists observed the merger of giant blackholes’ billions of light- years away from the Earth. What is the significance of this observation? (2019)
A. Higgs boson particles were detected.
B. Gravitational waves were detected.
C. Possibility of inter-galactic space travel through ‘wormhole’ was confirmed.
D. It enabled the scientists to understand ‘singularity’.
Answer: B
Explanation:
- The observation of the merger of giant black holes billions of light-years away from Earth is significant because it corresponds to the detection of gravitational waves. Gravitational waves are ripples in the fabric of spacetime caused by the acceleration of massive objects, such as the merging of black holes or neutron stars.
- In 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) made the groundbreaking detection of gravitational waves, confirming a major prediction of Albert Einstein’s General Theory of Relativity. The observation of black hole mergers using gravitational wave detectors has since become a powerful tool in astrophysics for studying extreme cosmic events and testing our understanding of gravity.
- The Higgs boson, a subatomic particle predicted by the Standard Model of particle physics, gained prominence with its discovery at the Large Hadron Collider (LHC) at CERN. Proposed as part of the mechanism to confer mass to elementary particles, the Higgs boson’s existence was independently theorized by physicists Peter Higgs, François Englert, and others. The monumental discovery was announced on July 4, 2012, by the ATLAS and CMS collaborations at CERN, marking a watershed moment in particle physics. The Higgs boson is intimately connected to the Higgs field, a pervasive force that endows particles with mass through their interactions. With a mass of approximately 125 gigaelectronvolts (GeV), the Higgs boson swiftly undergoes decay, offering scientists valuable insights into its properties. Post-discovery, researchers have diligently studied this particle, seeking to unravel its intricacies and refine our understanding of the fundamental building blocks of the universe. The Higgs boson’s detection at the LHC not only validated the Standard Model but also paved the way for deeper explorations into the mysteries of particle physics.
Q.13) “The experiment will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides one. million kilometres long, with lasers shining between the craft. The experiment in question refers to (2020)
A. Voyager-2
B. New Horizons
C. LISA Pathfinder
D. Evolved LISA
Answer: D
Explanation:
(a) Voyager-2:
- Description: Voyager-2 is a space probe launched by NASA in 1977. It has been on an extended mission to study the outer planets and has provided valuable data about Jupiter, Saturn, Uranus, and Neptune.
- Relevance: The described experiment is not related to Voyager-2. Voyager-2 is not designed for gravitational wave studies or the LISA project.
(b) New Horizons:
- Description: New Horizons is another NASA spacecraft launched in 2006 with the primary mission of studying Pluto and the Kuiper Belt.
- Relevance: Similar to Voyager-2, New Horizons is not associated with gravitational wave studies. It is focused on the exploration of distant celestial bodies.
(c) LISA Pathfinder:
- Description: LISA Pathfinder was a European Space Agency (ESA) mission launched in 2015. Its primary goal was to test technologies for future gravitational wave observatories in space.
- Relevance: LISA Pathfinder is directly related to the described experiment. It was a precursor mission for the LISA project, demonstrating key technologies needed for the detection of gravitational waves in space.
(d) Evolved LISA:
- Description: “Evolved LISA” could refer to an updated or advanced version of the LISA mission, which aims to detect and study gravitational waves in space.
- Relevance: This is the correct choice. The described experiment aligns with the objectives of LISA and evolved versions of the LISA mission, which involve spacecraft flying in formation to measure gravitational waves using laser interferometry.
