Core Concepts and Foundational Science

* Statement-I is incorrect: Giant stars do not live much longer than dwarf stars. In fact, giant stars have shorter lifespans compared to dwarf stars because they burn through their nuclear fuel at a much faster rate.

* Statement-II is correct: Compared to dwarf stars, giant stars have a greater rate of nuclear reactions. This is correct as giant stars are more massive and have higher pressures and temperatures in their cores, leading to faster nuclear fusion rates.

Nitric oxide (NO) is synthesized in the human body by the enzyme nitric oxide synthase from the amino acid arginine. It plays a crucial role in dilating blood vessels, which increases blood flow and reduces blood pressure. This function helps in regulating cardiovascular health.

_Why the other options are incorrect:_

B. Nitrous oxide: Used as an anesthetic, not a vasodilator.

C. Nitrogen dioxide: A toxic air pollutant, not involved in vasodilation.

D. Nitrogen pentoxide: A reactive compound, not related to blood vessel dilation.

Out of the listed effects of a major solar storm, the most likely ones are

Statement 1 is correct. A solar storm can disrupt the Earth's ionosphere, which can affect the signal transmission of GPS and other radio-based navigation systems.

Statement 3 is correct. Strong currents induced by the solar storm in power grids can damage transformers and cause widespread blackouts.

Statement 4 is correct. Solar storms can energize particles in the Earth's magnetosphere, leading to spectacular auroras at lower latitudes than usual.

Statement 6 is correct. The drag from a solar storm can alter the orbits of satellites, especially those in lower Earth orbit.

Statement 7 is correct. Similar to GPS, radio communication can be affected by disturbances in the ionosphere.

Statement 2 is incorrect. Tsunamis are caused by underwater earthquakes or volcanic eruptions, not solar storms.

Statement 5 is incorrect. While a solar storm could potentially ignite some fires through electrical sparks, this is not a widespread effect.

Therefore, codes 2 and 5 should not form the part of answer.

Statement 1 is correct: The size of the hole in the lid regulates the amount of steam released. A larger hole permits more steam to escape, leading to reduced pressure and subsequently affecting the temperature.

Statement 2 is incorrect: Boiling water can never exceed 100 degrees Celsius, regardless of the intensity of the flame beneath the pot. However, within a pressure cooker, the temperature can elevate to as high as 121 degrees Celsius. The heightened cooking temperature serves to decrease the cooking duration rather than the temperature itself.

Statement 3 is correct: If the weight is heavier, it will require higher pressure to lift it, resulting in higher pressure inside the cooker before excess steam can escape. Higher pressure leads to a higher boiling point for the water inside the cooker, which in turn increases the cooking temperature. Conversely, if the weight is lighter, it results in a lower pressure inside the cooker and a lower boiling point for the water, leading to a lower cooking temperature.

Statement A is incorrect: The distance between stellar bodies does change, but often very slowly or in predictable orbits. Planets orbit stars, stars orbit galactic centers, and galaxies orbit each other, all causing continuous changes in distance. And this statement is not related to why distance is measured in light years.

Statement B is incorrect: While the gravitational constant is fundamental, the effective gravity of stellar bodies changes due to shifts in their mass (e.g., fusion, stellar winds), changes in their radius/size (expanding into red giants, collapsing into white dwarfs/neutron stars), and changes in the distance between them as they orbit. And this statement is not related to why distance is measured in light years.

Statement C is incorrect: Though mostly light travels in a straight line, it can be bent by Gravity- phenomenon known as Gravitational Lensing.

Statement D is correct: the speed of light does not change in a vacuum. So, it is a constant that can be used for measurement.

Statement 1 is correct. Visible Light Communication (VLC) utilizes the electromagnetic spectrum within the visible light range, which is roughly between 375 nm (violet) and 780 nm (red).

Statement 2 is incorrect. VLC is not considered long-range communication compared to other optical wireless technologies like fibre optics. Its range is typically limited to shorter distances due to factors like signal power and signal degradation.

Statement 3 is correct. VLC has the potential to transmit large amounts of data at high speeds, often faster than Bluetooth technology, especially in scenarios where high data transfer rates are required.

Statement 4 is also correct. VLC does not use radio frequencies (RF) like traditional wireless communication technologies, and therefore, it does not suffer from electromagnetic interference (EMI) that can affect RF-based systems.

The description mentions three spacecraft in an equilateral triangle formation with million-kilometre sides using lasers for measurement. This matches the design of the Evolved Laser Interferometer Space Antenna (eLISA) mission. eLISA is a proposed space observatory aiming to detect gravitational waves using precisely positioned spacecraft.

Voyager-2 and New Horizons are single spacecraft on exploration missions, not designed for gravitational wave detection.

LISA Pathfinder was a precursor mission to test technologies for eLISA, not the full mission itself.

Therefore, based on the details provided, the experiment refers to the Evolved LISA mission.

The merger of black holes is expected to generate powerful gravitational waves.

Gravitational waves are ripples in spacetime caused by accelerating massive objects. Detecting these waves with instruments like LIGO (Laser Interferometer Gravitational-Wave Observatory) allows us to study these events even when they are too far away or obscured to observe directly. This opens a new window for astronomical observations.

Statement 1 is correct: According to Einstein's General Theory of Relativity, gravity can bend light. This phenomenon is known as gravitational lensing.

Statement 2 is correct: The General Theory of Relativity led to the prediction of an expanding universe, which has been confirmed by observational evidence.

Statement 3 is correct: According to the General Theory of Relativity, the presence of matter and energy warps the fabric of space and time around it, which is the underlying cause of the gravitational force.

So, all three statements are correct.

* The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are associated with the observation and understanding of the Universe, particularly in the field of cosmology and astrophysics.

* Event Horizon refers to the boundary around a black hole, beyond which nothing, not even light, can escape the black hole's gravitational pull.

* Singularity refers to a point in spacetime where the gravitational field becomes infinite, such as at the center of a black hole, where the laws of physics as we know them break down.

* String Theory is a theoretical framework in particle physics that attempts to unify all the fundamental forces of nature, including gravity, into a single coherent model.

* Standard Model is the most comprehensive and well-tested theory in particle physics, which describes the fundamental particles and their interactions, except for gravity.

Gravitational waves are ripples in the fabric of spacetime, predicted by Einstein's theory of general relativity.

eLISA is a space-based gravitational wave observatory that can detect and study these gravitational waves.

It is a joint project of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). eLISA is designed to detect gravitational waves from astronomical sources such as merging black holes and neutron stars. It would use laser interferometry to measure the tiny distortions in spacetime caused by passing gravitational waves. Detecting gravitational waves would provide important insights into the nature of gravity and the evolution of the universe.

The Goldilocks Zone, also called the habitable zone, refers to the region around a star where conditions might be just right for liquid water to exist on the surface of a planet.


Scientists believe liquid water is essential for life as we know it. So, when astronomers discover planets outside our solar system (exoplanets), they're particularly interested in those within the Goldilocks Zone of their host star.

IceCube is a particle detector at the South Pole that records the interactions of a nearly massless subatomic particle called the neutrino.

IceCube searches for neutrinos from the most violent astrophysical sources, events like exploding stars, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars.

Statement 1 is correct: IceCube is the world's largest neutrino detector, encompassing a cubic kilometre of ice.

Statement 2 is correct: The IceCube telescope is a powerful tool to search for dark matter and could reveal the physical processes associated with the enigmatic origin of the highest energy particles in nature.

Statement 3 is correct: It is buried beneath the surface, extending to about 2,500 meters. Burying it deep in ice is important to enhance the precision of the detector.

In addition to exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams.

Thus, all three statements are correct.

During photosynthesis, solar energy is converted into chemical energy and stored in sugar molecule bonds. This chemical bond energy is potential (stored) energy.


An optical illusion is a perception that differs from physical reality, often caused by atmospheric effects or the brain's processing of visual information.

Size of the sun at dusk is an optical illusion: The sun appears larger near the horizon than when it's high in the sky, even though its actual angular size is unchanged. This is a psychological illusion caused by our brain misinterpreting distance cues.

Colour of the sun at dawn is an optical illusion: The sun appears red because its light travels through more of the atmosphere, which scatters away blue light. This phenomenon, known as Rayleigh scattering, creates a perception of color that differs from the sun's actual light.

Moon being visible at dawn is not an optical illusion: This is a real astronomical event. The moon is often in a position in its orbit where it is bright enough to be seen during daylight hours.

The twinkle of stars in the sky is an optical illusion: Stars don't actually blink. Their light is refracted by turbulent layers in Earth's atmosphere, causing their apparent brightness to change rapidly, which we perceive as twinkling.

Polestar being visible in the sky is not an optical illusion: This is a real phenomenon based on celestial mechanics. The Polestar's apparent fixed position is due to its close alignment with the Earth's axis of rotation

Higgs Boson is a particle postulated by the Standard Model of Physics to provide mass to all particles in the universe.

Statement 1 is correct: Discovery of the Higgs Boson will help us further understand why elementary particles have mass.

Statement 2 is incorrect: The technology of transferring physical matter without traversing the physical space in between is not presently related to the discovery of the Higgs Boson.

Statement 3 is incorrect: The Higgs Boson will not help in creating better fuels for nuclear fission. It has to be understood that the discovery of the Higgs Boson will only confirm what has already been theorised and is not the discovery of a new principle in Physics.

Statement 1 is incorrect: The collision of clouds does not produce thunder.

Statement 2 is incorrect: Thunder is the sound produced by the rapid expansion of air due to the intense heat of lightning, not by the separation of clouds.

Statement 3 is incorrect: Strong updrafts contribute to cloud formation but do not directly cause thunder.

Thus, none of the above produces the thunder.

Explanation: Thunder is produced by the rapid expansion of air surrounding a lightning bolt, which creates a shock wave that we hear as sound. None of the options directly describes this mechanism.


Statement A is incorrect: Gravity is actually the weakest of the four fundamental forces for a given distance.

Statement B is correct: Electromagnetism acts only on charged particles, where the charge can be negative or positive.

Statement C is correct: The weak force is responsible for the existence and structure of atomic nuclei, including radioactivity and nuclear fusion.

Statement D is correct: Strong nuclear force is responsible for holding protons and neutrons together inside the atomic nucleus and is 100 times stronger than electromagnetism.

A ball bearing is a type of Rolling element bearing that uses the ball to maintain the separation between the bearing races. The purpose of round ball bearings is to reduce the surface area of contact between the object being moved and the one which is providing the power.

Thus, reduced area means less friction and more efficiency. The balls have a much lower coefficient of friction than the two flat surfaces sliding against each other.


Dispersion, Refraction and Internal reflection are all involved.

| Phenomenon | Role in rainbow formation | |------------|---------------------------| | Refraction | Sunlight bends when it enters the raindrop and again when it exits, changing direction at each air–water boundary. | | Dispersion | Different wavelengths refract by slightly different angles, so the white light spreads into its constituent colours inside the drop. | | Internal reflection | Part of the dispersed light reflects from the rear surface of the droplet and heads back toward the observer, making the coloured arc visible. |

Thus, the combined effect of Refraction → Dispersion → Internal Reflection → Refraction in order produces the familiar rainbow spectrum.