BPSC AE Paper 3 (General Studies) 10 Nov 2022 Official Paper (Previous Year Paper)

Concept:

1. Binocular Vision: - Humans have two eyes placed slightly apart on the face. - This arrangement allows for binocular vision, where both eyes can view the same object from slightly different angles.
2. Depth Perception: - Binocular vision enables depth perception. - Depth perception is the ability to judge the distance of objects and perceive the world in three dimensions.
3. Stereopsis:- Stereopsis is the process by which the brain combines the two different images from each eye to create a three-dimensional understanding of a scene. - This combined image allows us to perceive the depth of objects relative to each other.
4. Spatial Awareness: - Having two eyes enhances spatial awareness and helps in better coordination and navigation through complex environments.
5. Visual Cues: - Depth perception involves several visual cues, including binocular disparity, convergence, and other monocular cues like size, texture, and shading.

Explanation:

• Humans have two eyes positioned apart to enhance their ability to perceive depth, which is a critical aspect of interacting with their environment.
• Each eye captures a slightly different image due to the different angles of view. The brain processes these two images to create a single three-dimensional representation of the scene.
• This process, known as stereopsis, allows us to perceive the relative positions of objects in three-dimensional space and to estimate distances accurately.
• Height, area, and length can be perceived with one eye; depth, however, is significantly enhanced by binocular vision, providing a sense of how far away objects are and their spatial relationships.

Conclusion:

The correct answer is Depth

Concept:

1. **Line Grooves on Palms and Fingers:**These grooves are also known as dermatoglyphs (fingerprints and palm prints). - They form patterns that are unique to each individual.
2. Practical Function: - The primary function of these grooves is related to grip and tactile sensitivity.
3. Friction Ridges: - These ridges significantly increase the surface area of the skin, allowing for better contact with objects. - They enhance our ability to grip items more securely, especially when they are wet or slippery.
4. Tactile Sensitivity: - The grooves also play a role in tactile sensation, allowing us to detect fine textures and minute differences in surfaces.

Explanation:

• The fingerprints and grooves on our palms and fingers are not primarily for future prediction, static friction, or palmistry. Instead, these patterns serve a crucial biological function.
• The main role of these grooves is to enhance our grip.
• The unique patterns of ridges and grooves increase friction between our skin and the objects we hold, providing better traction.
• This is particularly important for tasks that require precise manipulation and strong grip, such as holding tools, climbing, or handling small objects.

Conclusion:

The correct answer is Gripping power

The correct answer is phase modulation

Key Points

• Phase modulation is commonly used for sending secret messages in information technology (IT).
• Phase modulation (PM) is a modulation pattern for conditioning communication signals for transmission.
• It is one of the most effective methods to encode digital data onto an analog carrier signal.
• In phase modulation, the phase of the carrier wave is varied in accordance with the message signal.

Additional Information

• Phase modulation is a type of angle modulation, similar to frequency modulation (FM).
• It is widely used in digital signal processing, particularly in communication systems.
• Phase modulation is less susceptible to noise and interference compared to amplitude modulation (AM).
• It is used in various applications, including satellite communications, radio broadcasting, and data transmission systems.
• Advanced encryption techniques can be employed along with phase modulation to enhance the security of transmitted messages.

Concept:

1. Earth's Atmosphere: The Earth has a thick atmosphere composed mainly of nitrogen, oxygen, and other gases. - Light from the Sun is scattered in all directions by the gases and particles in Earth's atmosphere. - Blue light is scattered more than other colors because it travels in shorter, smaller waves. This is why the sky appears blue during the daytime.
2. Moon's Lack of Atmosphere:- The Moon, on the other hand, has a very thin and negligible atmosphere, which is often referred to as an exosphere. - Without a significant atmosphere, there are no particles to scatter sunlight. - As a result, the sky on the Moon remains dark even when the Sun is shining.
3. Escape Velocity and Atmospheric Retention:- The Moon’s lower escape velocity means that it cannot retain a thick atmosphere because gas molecules have sufficient energy to escape the Moon’s gravitational pull. - This lack of atmosphere results in no scattering of light, leading to a dark sky.

Explanation:

• The key reason for the dark sky on the Moon, in contrast to Earth's blue sky, lies in the presence (or absence) of an atmosphere and the scattering of light.
• On Earth, the atmosphere scatters sunlight, particularly blue light, which makes the sky appear blue.
• The Moon, lacking such an atmosphere, does not scatter sunlight, and thus the sky remains dark.
• While the Moon's escape velocity and smaller size are related factors, the direct reason for the dark sky is its lack of a substantial atmosphere to scatter sunlight.

Conclusion:

The correct answer is Moon has less escape velocity

Concept:

1. Black Hole:- A black hole is an astronomical object with an extremely strong gravitational pull. - Its gravitational force is so intense that not even light can escape from it.
2. Mass and Size Relationship:- Black holes typically possess a very large mass condensed into an extraordinarily small volume. - This results in an extremely high density.
3. Event Horizon:- The boundary surrounding a black hole is known as the event horizon. - Once something crosses this boundary, it cannot escape the black hole's gravitational pull.
4. Gravitational Pull:- The immense gravitational pull of a black hole can draw in nearby stars, gas, and other cosmic material. - This process is often referred to as "eating" or "consuming" stars.

Explanation:

• Black holes are formed when massive stars collapse under their own gravity at the end of their life cycles.
• The resulting black hole retains much of the original star's mass but is incredibly small in volume, leading to a vast increase in density and gravitational pull.
• The gravitational attraction of a black hole is determined by its mass. Because black holes have a very large mass concentrated in a small area, they exert a powerful gravitational force capable of pulling in matter from their surroundings, including stars.

Conclusion:

The correct answer is It has large mass and small size

Concept:

1. Definition of Satellites:- Satellites are objects that orbit around a larger body in space. - They can be natural (like moons) or artificial/man-made.
2. Artificial Satellites:- Man-made satellites are launched into space using rockets. - They serve various purposes such as communication, weather monitoring, navigation, scientific research, and military applications.
3. Geostationary and Other Orbits:- Some satellites are in geostationary orbits, meaning they orbit the Earth at the same rate that the Earth rotates, staying over the same spot on the equator.
4. Free-Fall Under Gravity:- All satellites, whether natural or artificial, are in free-fall towards the Earth, but because of their high tangential velocity, they keep missing it, thus continuing their orbit.

Explanation:

• Satellites, including both natural ones (like the Moon) and man-made ones, stay in orbit around planets due to the balance between their velocity and the gravitational pull of the planet.
• Artificial satellites are launched using rockets and enter a state of continuous free-fall around the Earth. This free-fall, combined with their forward motion, creates a stable orbit.
• This is a fundamental aspect of orbital mechanics.
• Man-made satellites are indeed objects placed into orbit by humans, and while many are geostationary, not all of them are.
• They are subject to the laws of physics, including gravity, and thus are always in a state of free-fall towards Earth.

Conclusion:

The correct answer is Free-falling objects under gravity

The correct answer is Q-bits

Key Points

• Q-bits, also known as quantum bits, are the fundamental units of quantum information.
• Unlike classical bits, which can be either 0 or 1, Q-bits can exist in a superposition of states, enabling them to perform multiple calculations simultaneously.
• This property allows quantum computers to solve certain types of problems much faster than classical computers.
• Quantum entanglement and quantum superposition are key phenomena leveraged in quantum computing, making Q-bits essential for superfast computation.

Additional Information

• Quantum computing is a rapidly evolving field with significant implications for cryptography, optimization, and complex system simulations.
• Companies like IBM, Google, and Microsoft are at the forefront of developing quantum computers.
• Quantum algorithms, such as Shor's algorithm for factoring large numbers and Grover's algorithm for searching unsorted databases, demonstrate the potential of Q-bits in solving problems more efficiently than classical algorithms.

Concept:

1. Chain Reaction in Combustion:- In a combustion process, a chain reaction mechanism involves reactive intermediates that propagate the reaction by producing more intermediates.
2. Reactive Intermediates: - Common reactive intermediates in hydrogen-oxygen reactions include radicals such as H, O, and OH.
3. Chain Branching Propagators:- These are intermediates that, when involved in reactions, lead to the production of more reactive species, thus accelerating the reaction.

Explanation:

In the given hydrogen-oxygen chain reactions:

$\text{H}_2 + \text{O}_2 \rightarrow \text{HO}_2 + \text{H} \ \text{H}_2 + \text{HO}_2 \rightarrow \text{OH} + \text{H}_2\text{O} \ \text{OH} + \text{H}_2 \rightarrow \text{H}_2\text{O} + \text{H} \ \text{O}_2 + \text{H} \rightarrow \text{OH} + \text{O} \ \text{H}_2 + \text{O} \rightarrow \text{OH} + \text{H}$

The chain branching propagators in these reactions are the species that produce other reactive intermediates:

• Reaction 1: Produces H.
• Reaction 4: Produces OH and O.
• Reaction 5: Produces OH and H.

Therefore, the chain branching propagators identified are OH, H, and O.

Conclusion:

The correct answer is OH, H, O

Concept:

1. Thermal Decomposition of Aldehydes:- The process involves breaking the C-H bonds in the aldehyde molecule. - Involves radical intermediates leading to the formation of methane (or its isotoped variants) and carbon monoxide.
2. Isotopic Labeling:- CD3CDO is an isotopically labeled compound where deuterium (D) replaces hydrogen (H). - The radicals involved in the mechanism determine the distribution of hydrogen and deuterium in the products.

Explanation:

When we heat the mixture of CH3CHO (acetaldehyde) and CD3CDO (fully deuterated acetaldehyde), the expected reactions based on a simple interpretation are:

CH₃CHO → CH₄ + CO

CD₃CDO → CD₄ + CO

However, considering a radical mechanism, where intermediates can mix and exchange hydrogens and deuteriums, we have:

1. The radicals can recombine in various ways, leading to mixed isotopic products.
2. For instance, H and CD3, or CH3 and D, can recombine leading to methane with mixed isotopes.

This suggests the formation of partially deuterated methanes such as CH3D.

Conclusion:

The correct answer is CH₃D.

Concept:

1. First-Order Kinetics:- The rate of decomposition of a substance is often described by first-order kinetics, where the rate of change of concentration is proportional to the concentration.
2. Rate Law for First-Order Reactions:- The mathematical form of the first-order reaction is given by: Integrating this differential equation leads to an exponential decay function.

• $\frac{dC}{dt} = -kC$

Explanation:

The integrated form of the rate law for a first-order reaction is:

$\int \frac{1}{C} , dC = \int -k , dt$

The left side integrates to ln C) and the right side integrates to (-kt):

[ $\ln C = -kt + \text{constant of integration}$ ]

Exponentiate both sides to solve for ( C ):

[ $C = e^{-kt + \text{constant}}$} ]

To determine the constant, consider the initial condition when ( t = 0 ), ( C = C₀ ):

[ $C_0 = e^{\text{constant}}$]

Therefore, the constant is (ln C₀) and we can write:

$C = e^{\ln C_0} \cdot e^{-kt} = C_0 e^{-kt}$

• C = C₀ e^{-kt}

This equation indicates that the concentration of sucrose C decreases exponentially with time t and the rate constant k .

Conclusion:

The correct answer is C = C₀e^-kt

Concept:

Equilibrium Constant

For the dissociation reaction of oxygen:

$\text{O}_2 \leftrightarrow 2\text{O}$

The equilibrium constant K is defined as:

$K = \frac{[\text{O}]^2}{[\text{O}_2]}$

At high temperatures, the dissociation of O2  to oxygen atoms is more significant. However, at 1000 K, the equilibrium concentration of atomic oxygen (O) is generally quite low, indicating a small value for K .

Analysis of Given Options

1. 3.3 × 10-20

• This is a very low value, indicating very little dissociation of {O}_2 to {O} .

2. 2.5 × 10-10

• A small value representing minimal dissociation, but larger than option 1.

3. 5.2 × 10-7

• This value is higher and might be reasonable for some equilibrium reactions, but not typical for the dissociation of {O}_2 at 1000 K.

4. 1.4 × 10-37

• Extremely low, suggesting virtually no dissociation, which is unrealistic for a measurable equilibrium constant at 1000 K.

At 1000 K, oxygen molecules ( O2 ) do not dissociate significantly into oxygen atoms ( {O} ) due to the strong O=O double bond. The equilibrium constant for such a reaction is usually very small, but still within a measurable range.

Conclusion

The most reasonable equilibrium constant for the dissociation reaction of oxygen at 1000 K would be 2.5 × 10^-10

CONCEPT:

Molecular Orbital Theory for Diatomic Molecules

• Molecular orbital (MO) theory describes the distribution of electrons in molecules in terms of molecular orbitals that can extend over the entire molecule.
• In diatomic molecules, the combination of atomic orbitals from two atoms results in the formation of bonding and antibonding molecular orbitals.
• The given molecular orbital configuration represents the arrangement of electrons in these molecular orbitals.
• The specific configuration  $(2s\sigma_g)^2 (2s\sigma_u)^2 (2p\sigma_g)^2 (2p\pi_u)^4$ needs to be matched with a known diatomic molecule.

Explanation:-

• Total electrons in the configuration:
• (2s\sigma_g)² : 2 electrons
• (2s\sigma_u)² : 2 electrons
• (2p\sigma_g)² : 2 electrons
• (2p\pi_u)⁴ : 4 electrons
• Total number of electrons: 2 + 2 + 2 + 4 = 10
• The molecule with 10 valence electrons that matches this configuration is O₂ .

The given molecular orbital configuration of the diatomic molecule

$(2s\sigma_g)^2 (2s\sigma_u)^2 (2p\sigma_g)^2 (2p\pi_u)^4$stands for O₂

CONCEPT:

Photon Energy and Photolysis

• Photolysis is a chemical reaction in which a chemical compound is broken down by photons.
• The energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength, given by the equation E = hc/λ .
• h (Planck's constant) = 6.626 x 10^-34 Js .
• c (speed of light) = 3 x 10⁸ m/s .
• The energy needed for photolysis generally corresponds to the energy required to break specific chemical bonds in the molecule.

Explanation:-

• To cause photolysis of acetone ($\text{CH}_3)_2\text{CO}$ , we need to provide photons with sufficient energy to break its C–C and C=O bonds.
• The equation for the energy of a photon is E = hc/λ , where:
• h = 6.626 \times 10^-34 Js
• c = 3 \times 10^8 \text{ m/s}
• λ (wavelength) is in meters.
• We need to determine the photon wavelength (λ) that provides the appropriate energy for the photolysis:

The photolysis of acetone (\text{CH}_3)_2\text{CO} to produce ethane \text{C}_2\text{H}_6 and carbon monoxide \text{CO} requires a photon of wavelength (λ):

1. 3130 Å
2. 2950 Å
3. 2200 Å
4. 3300 Å

CONCLUSION:

The correct wavelength of the photon necessary for the photolysis of acetone is one that supplies sufficient energy to break the bonds in acetone. Given the options, the wavelength 2200 Å (option 3) corresponds to the highest photon energy, which is necessary to drive the photolysis reaction. Therefore, the answer is:

Answer: 3) 2200 Å

CONCEPT:

Photon Energy and Photolysis

• Photolysis is a chemical reaction in which a chemical compound is broken down by photons.
• The energy of a photon ( E ) is related to its wavelength ( λ ) by the equation:
• $E = \frac{hc}{λ}$
• To initiate photolysis, the energy of the photon must be at least equal to the bond dissociation energy required to break the relevant chemical bonds in the molecule.

DETAILED EXPLANATION AND CALCULATION:

• First, we need to convert the given wavelengths from Ångströms to meters, as the speed of light is in meters per second:

• $3130 \text{ Å} = 3130 \times 10^{-10} \text{ m} = 3.13 \times 10^{-7} \text{ m} \ 2950 \text{ Å} = 2950 \times 10^{-10} \text{ m} = 2.95 \times 10^{-7} \text{ m} \ 2200 \text{ Å} = 2200 \times 10^{-10} \text{ m} = 2.20 \times 10^{-7} \text{ m} \ 3300 \text{ Å} = 3300 \times 10^{-10} \text{ m} = 3.30 \times 10^{-7} \text{ m}$

• Next, we calculate the energy for each wavelength using the formula E = \frac{hc}{λ} :

• For $λ = 3.13 \times 10^{-7} \text{ m}$ :

• $E = \frac{6.626 \times 10^{-34} \text{ Js} \times 3 \times 10^8 \text{ m/s}}{3.13 \times 10^{-7} \text{ m}} \ E \approx 6.35 \times 10^{-19} \text{ J}$

• For $λ = 2.95 \times 10^{-7} \text{ m}$:

• $E = \frac{6.626 \times 10^{-34} \text{ Js} \times 3 \times 10^8 \text{ m/s}}{2.95 \times 10^{-7} \text{ m}} \ E \approx 6.74 \times 10^{-19} \text{ J}$

• For $λ = 2.20 \times 10^{-7} \text{ m}$:

• $E = \frac{6.626 \times 10^{-34} \text{ Js} \times 3 \times 10^8 \text{ m/s}}{2.20 \times 10^{-7} \text{ m}} \ E \approx 9.03 \times 10^{-19} \text{ J}$

• For $λ = 3.30 \times 10^{-7} \text{ m}$ :

• $E = \frac{6.626 \times 10^{-34} \text{ Js} \times 3 \times 10^8 \text{ m/s}}{3.30 \times 10^{-7} \text{ m}} \ E \approx 6.02 \times 10^{-19} \text{ J}$

CONCLUSION:

Among the given options, the wavelength that provides the highest energy photon is 2200A (option 3). This wavelength corresponds to E =9.03 x 10^-19 J , which is sufficient to break the chemical bonds in acetone during its photolysis to produce ethane ( $\text{C}_2\text{H}_6$) and carbon monoxide ( \CO} ). Therefore, the photolysis of acetone requires a photon of wavelength  2200 Å

CONCEPT:

Electrode Reaction:

The electrode reaction in acid solution:

$\text{Cu}^{2+} + \text{e}^- \rightarrow \text{Cu}^+$

• Standard Electrode Potential ( E° ) is the measure of the individual potential of a reversible electrode at standard state, which is 25°C (298 K), 1 M concentration for each ion participating in the reaction, and a partial pressure of 1 atmosphere for each gas.

Explanation:-

• Standard potentials for related copper reactions:
• $\text{Cu}^{2+} + 2 \text{e}^- \rightarrow \text{Cu} , E^\circ = 0.34 \text{ V} \ \text{Cu}^+ + \text{e}^- \rightarrow \text{Cu} , E^\circ = 0.52 \text{ V}$
• For the intermediate reaction:
• $\text{Cu}^{2+} + \text{e}^- \rightarrow \text{Cu}^+$
• We use the standard Gibbs free energy ( $\Delta G^\circ$ ) relation to standard potential ( E° ):
• $\Delta G^\circ = -nFE^\circ$ where n is the number of moles of electrons, and F is the Faraday constant ( 96485  C/mol ).
• Consider the potential for the reduction from $\text{Cu}^{2+} to \ \ \text{Cu}$ :
• $E^\circ (\text{Cu}^{2+}/\text{Cu}) = 0.34 \text{ V} \ E^\circ (\text{Cu}/\text{Cu}^+) = -0.52 \text{ V} (reverse reaction) \ E^\circ (\text{Cu}^{2+}/\text{Cu}^+) = 0.34 + 0.52 = 0.86 \text{ V}$

The correct standard electrode potential for the given reaction $\text{Cu}^{2+} + \text{e}^- \rightarrow \text{Cu}^+$ is 0.306 V

CONCLUSION:

After considering the standard potentials, the value that matches is 0.306 V

Explanation and Calculation:

• Bond Dissociation Energies (approximate values):
• C-H bond inC2H6 : 413 kcal/mol
• C-C bond in C2H6 : 348 kcal/mol
• H-H bond: 436 kcal/mol
• C-H bond in CH₄ : 413 kcal/mol
• Total Bond Dissociation Energy:
• For C2H6 :
• 1 x 348 + 6 x 413 = 2826 kcal
• For H₂ :
• 1 x 436 = 436 kcal
• Total energy to break bonds:
• 3262 kcal
• Total Bond Formation Energy:
• For 2 CH₄ :
• 2 x (4 x 413) = 3304 kcal
• Total energy to form bonds:
• 3304 kcal
• Heat Change ( \Delta H ) for the reaction:
• $\Delta H = \text{Energy of bonds broken} - \text{Energy of bonds formed} \ \Delta H = 3262 \text{ kcal} - 3304 \text{ kcal} = -42 \text{ kcal}$
• Convert to calories:
• $\Delta H = -42000 \text{ cal}$

Conclusion:

The heat change for this reaction is closest to 41745 cal

Concept:-

Given a chemical reaction that is 20% complete in:

• 15 minutes at 40 °C (313 K)
• 3 minutes at 60 °C (333 K)

Using the Arrhenius equation:

$k = A e^{-E_a / RT}$

The logarithmic form of the Arrhenius equation is:

$ln(k2 / k1) = (E_a / R) (1/T1 - 1/T2)$

Explanation:-

• Determine the rate constant ratio using the times:
• k2 / k1 = 15 min / 3 min = 5
• Using the temperatures T1 = 313 K, T2 = 333 K:
• 1 / 313 - 1 / 333 = (333 - 313) / (313 x 333) ≈ 0.000192
• Substitute into the Arrhenius equation:
• $ln(5) = (E_a / 1.987) x 0.000192$
• ln(5) ≈ 1.60944
• $E_a = (1.60944 / 0.000192) x 1.987 ≈ 16.4 kcal/mol$

Therefore, the activation energy required is​ 16.4 kcal

Explanation:-

The conductivity of a saturated AgCl solution in water at 20 °C is higher by 11.26 × 10-6 ohm-1 cm-1  than the pure water conductivity.

Consider the dissociation of AgCl 

$\text{AgCl} \rightarrow \text{Ag}^+ + \text{Cl}^-$

The total conductivity \kappa of the solution is 

$\kappa = c \times \Lambda^\circ_\text{m}$

Given data:

• Increase in conductivity $( \Delta \kappa ): 1.26 \times 10^{-6} \text{ ohm}^{-1} \text{ cm}^{-1}$
• Molar conductivities at infinite dilution:
• $\lambda^\circ_{\text{Ag}^+} \approx 61.9 \text{ S cm}^2 \text{ mol}^{-1} \ \lambda^\circ_{\text{Cl}^-} \approx 76.3 \text{ S cm}^2 \text{ mol}^{-1}$

Calculate the molar conductivity of {AgCl :

• $\Lambda^\circ_\text{m} (\text{AgCl}) = \lambda^\circ_{\text{Ag}^+} + \lambda^\circ_{\text{Cl}^-} \ \Lambda^\circ_\text{m} (\text{AgCl}) = 61.9 + 76.3 = 138.2 \text{ S cm}^2 \text{ mol}^{-1}$

Using the relation for conductivity and solubility ( c ):

$1.26 \times 10^{-6} \text{ ohm}^{-1} \text{ cm}^{-1} = c \times 138.2 \times 10^{-6} \text{ ohm}^{-1} \text{ cm}^2 \text{ mol}^{-1}$

Solve for c (solubility):

$c = \frac{1.26 \times 10^{-6}}{138.2 \times 10^{-6}} \text{ mol/L}$

• $c \approx \frac{1.26}{138.2} = 0.00912 \times 10^{-6} \ c \approx 9.12 \times 10^{-6} \text{ mol/L}$

Therefore, the solubility of AgCl in water is 9.14 × 10^-6 moles liter^-1

The correct answer is modifiers

Key Points

• Ctrl, Shift, and Alt keys are known as modifier keys.
• Modifier keys are used in conjunction with other keys to perform special operations or shortcuts.
• For example, pressing Ctrl + C copies the selected text or item, while Ctrl + V pastes it.
• Modifier keys do not function alone and are designed to alter the function of other keys when pressed together.

Additional Information

• Modifier keys are essential for using keyboard shortcuts efficiently and can significantly speed up tasks.
• Other examples of modifier keys include the Command key on Mac keyboards and the Windows key on Windows keyboards.
• Understanding the use of modifier keys can enhance productivity and provide advanced control over software applications.

The correct answer is operating system

Key Points

• A computer cannot boot without an operating system.
• The operating system is essential for managing the hardware and software resources of the computer.
• It provides the necessary interface for users to interact with the computer system.
• Without an operating system, the computer hardware cannot function effectively or efficiently.

Additional Information

• An operating system (OS) is a software that acts as an intermediary between computer hardware and the computer user.
• Popular examples of operating systems include Windows, macOS, Linux, and Unix.
• The primary functions of an OS include managing the computer's memory, processing, software and hardware, and handling input and output operations.
• In the absence of an OS, users would not be able to run application software on their computers.

The correct answer is spam

Key Points

• Spam is the correct term for junk e-mail.
• Spam refers to unsolicited and often irrelevant or inappropriate messages sent over the internet, typically to a large number of users, for the purposes of advertising, phishing, spreading malware, etc.
• Other options provided, such as spoof, sniffer script, and spool, do not refer to junk e-mail.
• Spoof refers to the act of disguising a communication from an unknown source as being from a known, trusted source.
• Sniffer script is a type of software used to monitor and analyze network traffic.
• Spool refers to the process of placing data into a temporary working area for another program to process later.

Additional Information

• Spam can be a significant problem in terms of both the volume of unwanted messages and the potential risks associated with malicious content.
• There are various methods to combat spam, including spam filters, blacklists, and user education.
• Legislation like the CAN-SPAM Act in the United States aims to regulate commercial emails and reduce spam.
• Users are advised to be cautious about sharing their email addresses and to use email filtering tools to manage unsolicited messages.

The correct answer is network

Key Points

• Several computers linked to a server to share programs and storage space are called a network.
• A network allows multiple computers to communicate, share resources, and access shared data.
• Networks can be local (LAN) or wide-area (WAN), depending on the geographical area they cover.
• Networks improve efficiency and collaboration by enabling centralized management and data sharing.

Additional Information

• Common types of networks include Local Area Networks (LAN), Wide Area Networks (WAN), and Metropolitan Area Networks (MAN).
• Networking technologies include Ethernet, Wi-Fi, and Bluetooth.
• Network security is crucial to protect data and maintain privacy.
• Network devices include routers, switches, and firewalls.

The correct answer is Browser

Key Points

• A Browser is a software application used to access and view websites.
• Common web browsers include Google Chrome, Mozilla Firefox, Safari, and Microsoft Edge.
• Browsers interpret and display HTML code, allowing users to navigate between web pages via hyperlinks.
• They also support various web technologies and standards like CSS, JavaScript, and multimedia content.

Additional Information

• Web browsers also provide features like bookmarking, history, and tabbed browsing.
• They can be extended with plugins and extensions to enhance functionality.
• Security features such as private browsing, pop-up blockers, and phishing protection are also integrated into modern browsers.
• Browsers are essential tools for accessing the vast information and services available on the World Wide Web.

Correct Answer: Secondary

Key PointsA USB flash drive is a secondary storage device. It is a non-volatile memory used to store data permanently and retain it even when power is turned off. It is mainly used for data storage, backup, and transfer between computers, not for direct execution like primary memory (RAM).

Why other options are incorrect:

• Primary: Refers to main memory like RAM and ROM, which a USB flash drive is not.
• Virtual: Virtual memory is a technique using secondary storage to extend RAM, not a physical device.
• Tertiary: Used for large-scale archival storage (like tape libraries), not USB drives.

Final Answer: Secondary

The correct answer is Character

Key Points

• Character is the correct answer for the abbreviation MICR, where C stands for Character.
• MICR stands for Magnetic Ink Character Recognition.
• It is a technology used to verify the legitimacy or originality of paper documents, especially checks.
• MICR encoding, called the MICR line, is at the bottom of checks and other vouchers and typically includes the document-type indicator, bank code, bank account number, check number, and the amount, plus a control indicator.
• The technology is used mainly by the banking industry to facilitate the processing and clearance of checks and other documents.

Additional Information

• Magnetic Ink is used in the printing of certain characters on the original documents, which can be read by machines.
• This technology helps in speeding up the processing of documents and reduces errors that can occur during manual processing.
• MICR characters are printed in a special font and contain magnetic ink or toner, which allows them to be read by MICR readers.
• The use of MICR provides a high level of security, as the characters are difficult to forge and can be easily verified.

The correct answer is LAN.

Key Points

• LAN stands for Local Area Network.
• A LAN is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus, or office building.
• LANs are characterized by higher data transfer rates, smaller geographic areas, and lack of a need for leased telecommunication lines.
• They are used to connect personal computers and workstations in company offices and factories to share resources (e.g., printers) and exchange information.

Additional Information

• DSL (Digital Subscriber Line) is a technology for high-speed network or internet access over telephone lines.
• RAM (Random Access Memory) is a type of computer memory that can be accessed randomly.
• USB (Universal Serial Bus) is a standard for cables, connectors, and protocols for connection, communication, and power supply between computers and electronic devices.

The correct answer is strong security kernel

Key Points

• Strong security kernel is a significant factor contributing to the superiority of the LINUX operating system.
• LINUX is known for its robust security features, which include strong user permissions, encryption, and a secure boot process.
• The security kernel in LINUX helps protect the system against various types of malware and unauthorized access.
• Due to its open-source nature, LINUX benefits from continuous security audits and updates from the global community of developers.

Additional Information

• LINUX is an open-source operating system kernel first released on September 17, 1991, by Linus Torvalds.
• It is widely used in various environments, including servers, desktops, and embedded systems.
• LINUX distributions, such as Ubuntu, Fedora, and CentOS, are built on the LINUX kernel and offer user-friendly interfaces and additional software packages.
• LINUX's open-source nature allows users to customize and optimize the operating system according to their specific needs.
• Many of the world's servers, supercomputers, and cloud infrastructures run on LINUX due to its reliability and security.

The correct answer is 62 and 8

Key Points

• AAP won 62 seats in the Delhi election held on February 8, 2020.
• BJP won 8 seats in the same election.
• The election was a significant event, showcasing the political landscape and voter preferences in the capital city of India.
• The results reflected a strong mandate for the AAP, allowing them to form the government in Delhi.

Additional Information

• The Delhi Legislative Assembly election is held every five years to elect 70 members.
• The Aam Aadmi Party (AAP) is led by Arvind Kejriwal, who has been a prominent figure in Delhi politics.
• The Bharatiya Janata Party (BJP) is one of the major national parties in India and has a significant presence across the country.
• Delhi, being the national capital, holds a crucial position in India's political scenario.
• The voter turnout in the 2020 Delhi election was around 62.59%.

The correct answer is Sri Lanka

Key Points

• Prime Minister of Sri Lanka visited India during the period 7 - 10 February, 2020.
• This visit was aimed at strengthening bilateral relations between India and Sri Lanka.
• During the visit, discussions on various topics such as defense, economic cooperation, and cultural exchanges were held.
• The visit highlighted the importance of close ties and cooperation between the two neighboring countries.

Additional Information

• The visit of the Sri Lankan Prime Minister was part of ongoing efforts to enhance bilateral relations between India and Sri Lanka.
• India and Sri Lanka share deep historical and cultural ties, and both countries have been working together on various regional and international platforms.
• Key areas of cooperation include trade, investment, education, and technology.
• Both countries are committed to working together to promote peace, stability, and prosperity in the South Asian region.

The correct answer is Denmark and Somalia.

Key Points

• Denmark is considered the least corrupt country according to the 2019 Report of the Transparency International.
• Somalia is considered the most corrupt country according to the same report.
• Transparency International's Corruption Perceptions Index (CPI) ranks countries by their perceived levels of public sector corruption, as determined by expert assessments and opinion surveys.
• Denmark consistently ranks at the top due to its strong institutions, transparency, and rule of law.
• Somalia, on the other hand, struggles with ongoing conflict, weak institutions, and lack of governance, leading to high levels of corruption.

Additional Information

• Transparency International is a global organization that works to combat corruption and prevent criminal activities arising from corruption.
• The Corruption Perceptions Index (CPI) is a composite index that draws on multiple expert opinions and surveys to measure perceived levels of public sector corruption.
• The CPI is widely used as a benchmark for assessing the corruption levels in different countries.
• Countries with higher scores are perceived to be less corrupt, while those with lower scores are perceived to be more corrupt.
• Efforts to combat corruption often focus on improving transparency, strengthening institutions, enforcing laws, and promoting good governance practices.

The correct answer is John Roberts

Key Points

• John Roberts is the Chief Justice of the United States Supreme Court.
• He presided over the impeachment trial of President Donald Trump.
• The Chief Justice plays a crucial role in overseeing the proceedings and ensuring that the trial follows legal protocols.
• John Roberts has been serving as the Chief Justice since 2005, appointed by President George W. Bush.
• His role in the impeachment trial was to maintain order and provide rulings on procedural questions.

Additional Information

• The impeachment process is outlined in the United States Constitution.
• The House of Representatives has the sole power to impeach, while the Senate has the sole power to try impeachments.
• During an impeachment trial, the Chief Justice presides over the Senate when the President of the United States is being tried.
• Impeachment does not necessarily result in removal from office; it requires a two-thirds majority vote in the Senate for conviction and removal.
• President Trump was impeached twice by the House but was acquitted both times by the Senate.

The correct answer is Morarji Desai

Key Points

• Morarji Desai was the Prime Minister of India when USA President Jimmy Carter visited India.
• Jimmy Carter, the 39th President of the United States, visited India in January 1978.
• Morarji Desai served as the Prime Minister of India from 1977 to 1979.
• During Carter's visit, discussions were held on various bilateral issues, including economic and technological cooperation.

Additional Information

• Indira Gandhi was the Prime Minister of India prior to Morarji Desai, serving until 1977.
• Morarji Desai was the first non-Congress Prime Minister of India, leading the government formed by the Janata Party.
• His tenure is noted for efforts to strengthen democratic institutions and reduce government control in various sectors.
• Jimmy Carter's visit to India was part of his broader foreign policy initiative to strengthen ties with developing countries and promote human rights.
• The visit marked a significant moment in Indo-US relations, with both nations expressing a desire for closer cooperation.

The correct answer is 111.2 million tons

Key Points

• 111.2 million tons is the record steel production in India for the year 2019.
• The total Indian steel production was 109.3 million tons in 2018.
• This indicates an increase in steel production by 1.9 million tons from 2018 to 2019.
• The growth in steel production reflects the overall growth and development in the industrial sector of India.

Additional Information

• India is one of the largest producers of steel in the world, contributing significantly to the global steel industry.
• The steel sector is a major contributor to the Indian economy, providing employment and supporting infrastructure development.
• Advancements in technology and increased investments have played a crucial role in boosting steel production in the country.
• The government of India has been implementing various policies to support and enhance the growth of the steel industry.
• India's steel production capacity is expected to further increase in the coming years, driven by domestic demand and export opportunities.

The correct answer is 430

Key Points

• 430 is the population density (per square kilometer) in India as per the last report.
• The population density is a measure of the number of people living per unit area, which in this case is per square kilometer.
• It is an important demographic indicator that helps understand the distribution of population in the country.
• High population density areas often face challenges related to infrastructure, resources, and services.

Additional Information

• India is the second most populous country in the world.
• The population density varies significantly across different states and regions in India.
• Urban areas tend to have much higher population densities compared to rural areas.
• Accurate data on population density helps in planning and allocation of resources by the government.

The correct answer is 13 and 4.

Key Points

• Gully Boy received 13 Filmfare awards.
• Parasite received 4 Oscar awards.
• Gully Boy is a Bollywood film directed by Zoya Akhtar and was highly acclaimed in India.
• Parasite is a South Korean film directed by Bong Joon-ho and gained international acclaim, including winning the Best Picture at the Oscars.

Additional Information

• Gully Boy was inspired by the lives of Indian street rappers Divine and Naezy.
• Parasite made history as the first non-English language film to win the Best Picture award at the Oscars.
• Parasite also won awards for Best Director, Best Original Screenplay, and Best International Feature Film at the Oscars.
• Gully Boy received awards across multiple categories including Best Film, Best Director, and Best Actor at the Filmfare Awards.

The correct answer is 11th February

Key Points

• Safer Internet Day is celebrated on 11th February.
• It is an international event that aims to promote safer and more responsible use of online technology and mobile phones, especially among children and young people.
• The day is organized by the Insafe/INHOPE network of Safer Internet Centres in Europe, with the support of the European Commission.
• Safer Internet Day is celebrated in approximately 150 countries worldwide.
• The event features various activities and campaigns to raise awareness about online safety, cyberbullying, and the importance of digital literacy.

Additional Information

• Safer Internet Day was first initiated in 2004 as part of the EU SafeBorders project.
• Each year, Safer Internet Day has a specific theme; for example, the theme for 2023 was "Together for a better internet".
• The event encourages everyone to join the movement, to participate, and to make the most of the internet's potential to bring people together.
• Various stakeholders, including governments, organizations, educators, parents, and young people, collaborate to make the internet a safer and better place.

The correct answer is 9th

Key Points

• The budget submitted by Minister Sushil Modi on 25th February, 2020, was the 9th in the serial order of the list.
• This budget pertains to the state of Bihar, indicating the fiscal planning and allocation of resources for the state for the upcoming financial year.
• Budget presentations are crucial for outlining the government's revenue and expenditure plans and are typically followed by discussions and approvals in the legislative assembly.

Additional Information

• The state budget is an important financial document that reflects the government's policy priorities and development agenda.
• It includes various allocations for sectors such as education, health, infrastructure, and welfare schemes.
• Budgets are presented annually and require the approval of the state legislature.
• Effective budget management is critical for the economic stability and growth of the state.

The correct answer is Vyommitra.

Key Points

• Vyommitra is the name of the 'half-humanoid' robot developed by ISRO for the Chandrayaan-3 project.
• Vyommitra is designed to simulate human functions in space, providing data and feedback on various conditions and experiments during the mission.
• This half-humanoid robot can perform multiple tasks, including operating equipment, and will help in enhancing the efficiency of the mission.
• Vyommitra is part of ISRO's efforts to advance in space exploration and technology, focusing on safety and reducing the risks associated with human space travel.

Additional Information

• The Chandrayaan-3 mission is a follow-up to Chandrayaan-2, aimed at demonstrating safe and soft landing on the lunar surface.
• ISRO, the Indian Space Research Organisation, has been at the forefront of space research and has achieved significant milestones, including the Mars Orbiter Mission (Mangalyaan).
• Vyommitra's development is part of ISRO's larger vision to include human spaceflight in its future missions, with the Gaganyaan project being a notable example.
• ISRO continues to innovate and contribute to global space research, with various international collaborations and partnerships.

The correct answer is 42nd

Key Points

• GSAT-30 is the 42nd communication satellite launched by ISRO.
• The satellite was launched on 17th January 2020 from the Guiana Space Centre in Kourou, French Guiana.
• GSAT-30 is designed to replace the INSAT-4A satellite and provide continuity of services on operational satellites in C-band, extended C-band, and Ku-band.
• It is intended to provide high-quality television, telecommunications, and broadcasting services.
• The satellite is equipped with 12 C-band and 12 Ku-band transponders to provide coverage over India, Gulf countries, a large number of Asian countries, and Australia.

Additional Information

• ISRO (Indian Space Research Organisation) is the space agency of the Government of India, headquartered in Bengaluru.
• ISRO's vision is to "harness space technology for national development while pursuing space science research & planetary exploration".
• The organization was founded in 1969 and has since developed a robust space program that includes satellite launch vehicles, satellites, and interplanetary missions.
• ISRO's achievements include the Mars Orbiter Mission (Mangalyaan), Chandrayaan missions to the Moon, and the development of the Geosynchronous Satellite Launch Vehicle (GSLV).

The correct answer is 2016

Key Points

• 2016 was the hottest year on record according to the climate monitoring agency "Copernicus Climate Change Service".
• The agency monitors and analyzes climate data to track changes in global temperatures and other climate-related metrics.
• 2016 was marked by significant global temperature anomalies, leading to record-breaking heat.
• This year saw widespread impacts from heatwaves, droughts, and other climate extremes.
• The data underscores the urgent need for global climate action to mitigate the effects of climate change.

Additional Information

• Copernicus Climate Change Service (C3S) is an operational service that provides comprehensive climate information covering a wide range of sectors.
• The service is part of the European Union's Earth observation program, Copernicus, which aims to provide accurate, timely, and easily accessible information to improve environmental management and to understand and mitigate the effects of climate change.
• 2016's record temperatures were influenced by a strong El Niño event, which contributed to higher global temperatures.
• Continued monitoring and analysis of climate data are essential for developing effective strategies to address and adapt to climate change.

The correct answer is Period-End of Sentence.

Key Points

• Period-End of Sentence is the name of the Oscar Award-winning short Indian film.
• The film won the Oscar for Best Documentary (Short Subject) at the 91st Academy Awards in 2019.
• Directed by Rayka Zehtabchi, the film addresses the stigma around menstruation in rural India.
• The documentary was produced by Guneet Monga's Sikhya Entertainment.
• It highlights the efforts of women in a rural village in India to produce sanitary pads and improve menstrual hygiene.

Additional Information

• The 91st Academy Awards ceremony was held on February 24, 2019.
• Rayka Zehtabchi is an Iranian-American filmmaker known for her work on socially relevant topics.
• Guneet Monga is a renowned Indian film producer who has been involved in several critically acclaimed projects.
• The film has been praised for its impactful storytelling and its role in raising awareness about menstrual hygiene.
• It has inspired many initiatives aimed at promoting menstrual health and breaking the taboos associated with it.

The correct answer is Bhalkunda.

Key Points

• Bhalkunda is not situated on the river Narmada.
• The other waterfalls mentioned (Dugdhdhara, Bheraghat, and Kapildhara) are all located on the river Narmada.
• The river Narmada is known for its scenic beauty and numerous waterfalls along its course.

Additional Information

• The Narmada River, also known as the Rewa, is one of the major rivers in central India and flows westward over a length of about 1,312 km before draining into the Arabian Sea.
• It is one of the seven holy rivers of India and has significant cultural and religious importance.

The correct answer is Ziauddin Barani.

Key Points

• Ziauddin Barani is the author of Tarikh-i-Firoz Shahi.
• Barani was a Muslim historian from the Delhi Sultanate during the 14th century.
• His work, Tarikh-i-Firoz Shahi, is an important historical text that provides a detailed account of the reign of Sultan Firoz Shah Tughlaq.
• It covers various aspects of the administration, society, and events of that period.
• Barani's writings are considered a valuable source of information for understanding the history and culture of medieval India.

Additional Information

• Barani was a contemporary of other notable historians like Ibn Battuta and Amir Khusrau.
• His other significant work includes "Fatwa-i-Jahandari".
• Tarikh-i-Firoz Shahi is not just a historical record but also provides insights into the political and social norms of the time.
• Barani's perspective was influenced by his own experiences and the political environment of the Delhi Sultanate.

Explanation:-

Formation of a Rainbow:

A rainbow is formed in the sky due to several physical phenomena involving the interaction of sunlight with water droplets. The key steps include:

1. Refraction: As sunlight enters a water droplet, it slows down and bends because light travels slower in water than in air.
2. Dispersion: The refraction causes the light to disperse into its component colors because different wavelengths (colors) of light refract at different angles.
3. Total Internal Reflection: The dispersed light reflects off the inner surface of the water droplet. This reflection is nearly total, meaning most of the light stays within the droplet.
4. Refraction (again): The light exits the water droplet, and as it does, it bends again. This final bending makes the colors more distinct and forms the visible spectrum of a rainbow.

Given the options, the correct sequence of phenomena involved in the formation of a rainbow is total internal reflection - dispersion - refraction

Explanation:-

When applying a stable metal coating on another metal, the thickness is typically measured in micrometers. This is because:

• Micrometer Scale: A micrometer (µm) is 1 millionth of a meter, or 1 thousandth of a millimeter, providing a practical and economical thickness for protection and functionality.
• Nanometer Scale: While nanometer coatings are used in specialized applications, they might be too thin for general use.
• Millimeter/Centimeter Scales: These scales are too thick for coatings and would typically be considered layers or claddings.

Typical Thickness Ranges:

• Electroplating: 1-30 micrometers
• Galvanization: 5-25 micrometers
• Anodizing: 5-25 micrometers
• PVD and CVD Coatings: several nanometers to several micrometers, with typical industrial coatings in the micrometer range

Given these factors, the optimal thickness for a stable metal coating on another metal is micrometer

Explanation:-

Reason for Using Steel in Engineering Tools and Machines:

Steel is extensively used in engineering tools and machines for several important reasons:

• Durability: Steel is exceptionally durable, capable of withstanding significant wear and tear, high stress, and harsh environmental conditions.
• Strength: It has a high tensile strength, essential for bearing heavy loads without deforming.
• Versatility: Steel can be alloyed and treated to enhance properties like hardness, toughness, and corrosion resistance.
• Cost-effectiveness: While steel is affordable and readily available, its performance characteristics are the primary reason for its widespread use.

Given these factors, the primary reason for using steel in most engineering tools and machines is more durability

Explanation:-

Mechanism of Heat Conduction in Solids:

Heat conduction in solids is primarily due to two mechanisms:

• Phonons: Phonons are quantized lattices vibrations and play a major role in conducting heat in non-metallic solids. Even in metals, phonon interactions contribute to thermal conductivity.
• Electrons: In metals and conductors, free electrons significantly contribute to heat conduction due to their mobility and ability to transfer energy across the lattice.

Other options:

• Protons: Protons are confined within the atomic nucleus and do not participate in heat conduction in solids.
• Photons: Photons are particles of light that can transfer heat via radiation but not conduction in solids.

So the generalized context of heat conduction in solids, the correct answer is phonons

Explanation:-

• Metals expand in dimensions when heated due to the increased vibrational energy of the atoms within the metal.
• This increase in vibrational energy causes the atoms to move more vigorously and occupy a greater average distance, leading to thermal expansion.

This vibrational energy can be described in terms of phonons, which are quantized modes of vibrations of the crystal lattice.

• Phonons: Phonons represent the vibrational energy of atoms in the solid's lattice. Increased phonon energy with temperature leads to greater atomic vibrations and thus expansion.
• Heat: Heat is the transfer of thermal energy which raises the temperature, but it is the resultant phonon energy that directly causes expansion.
• Electrons: While electrons contribute to thermal conductivity, they are not the primary factor in thermal expansion.
• Photons: Photons are involved in radiative heat transfer rather than the mechanical expansion of a solid.

Given these explanations, the correct answer is phonons

Explanation:-

Detergents are effective at cleaning clothes in washing machines for the following reason:

• Low temperature: While temperature can influence the effectiveness of detergents, they do not primarily clean by lowering the temperature of water.
• Low surface tension: Detergents lower the surface tension of water. This allows the water to more effectively penetrate fabrics, emulsify oils, and break up dirt. Reduced surface tension ensures that water spreads and wets surfaces better, which is crucial for the cleaning process.
• Low weight: The weight of water is unrelated to the cleaning action of detergents.
• Low density: The density of water remains largely unchanged with detergent and does not impact the cleaning process.

Therefore, the reason detergents clean clothes is that they reduce the water's surface tension, enhancing its ability to interact with and clean the fabrics is low surface tension

Explanation:-

The primary mechanism allowing trees to pull water from deep within the ground is:

• Mineral water: Refers to the composition of water and its dissolved minerals, not the mechanism of transport.
• Capillary action: This is the key process. Capillary action involves the movement of water through the narrow tubes (xylem) within the tree. It is driven by the adhesive forces between water molecules and the walls of the xylem vessels, and the cohesive forces between the water molecules themselves.
• Photosynthesis: This is the process by which trees convert light energy into chemical energy, but it does not directly relate to water transport from the ground.
• Wood nature: The characteristics of wood affect water transport efficiency but do not explain the transport mechanism.

Therefore, trees pull water from the ground primarily due to the property of capillary action is capillary action

Explanation:-

When body feel tired, we often sit down or lie flat to achieve:

• Body center of gravity: While changing posture affects our center of gravity, this is not the main reason for resting.
• Body low gravity potential: Lowering gravity potential is not the primary reason we choose to sit or lie down when tired.
• Body low temperature: Sitting or lying down is not primarily aimed at regulating body temperature.
• Body relaxation: The main reason we sit or lie down when feeling tired is to achieve relaxation. These positions help reduce muscle strain, provide comfort, and facilitate rest and recovery.

Therefore, the primary reason for sitting down or sleeping flat when tired is to promote body relaxation.