Question 1

Consider the following types of vehicles:
1. Full battery electric vehicles
2. Hydrogen fuel cell vehicles
3. Fuel cell electric hybrid vehicles

How many of the above are considered as alternative powertrain vehicles?

Accepted Answer

Only two. * A powertrain is the system in a vehicle that generates power and delivers it to the wheels (engine, transmission, drivetrain, axles, differentials, etc.). * All three vehicle types are considered alternative powertrain vehicles because they use non-conventional propulsion systems compared to traditional internal combustion engines (ICE). * I. Full battery electric vehicles (BEVs) are powered entirely by electricity stored in batteries and use non-ICE systems. * II. Hydrogen fuel cell vehicles (FCEVs) use hydrogen fuel cells to generate electricity to power electric motors. * III. Fuel cell-electric hybrid vehicles combine a fuel cell with a battery or other electric storage system.

Question 2

With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements:
I. All types of UAVs can do vertical landing.
II. All types of UAVs can do automated hovering.
III. All types of UAVs can use battery only as a source of power supply.

How many of the statements given above are correct?

Accepted Answer

All the three. * Statement I is incorrect: A type of drone known as a fixed-wing drone utilizes rigid wings, a fuselage, tails, a propeller, and a motor to cover long distances at high speeds. Unlike multirotor drones, they cannot do vertical landing and require a runway or a net. * Statement II is incorrect: For the same reason, traditional fixed-wing drones cannot perform automated hovering at specific points in the air. * Statement III is incorrect: UAVs come in many configurations, including high-endurance military UAVs (e.g., Predator drones). Due to power and endurance limits (as the energy density of batteries is lower than fuel), long-range or military UAVs cannot rely solely on batteries.

Question 3

In the context of electric vehicle batteries, consider the following elements:
I. Cobalt
II. Graphite
III. Lithium
IV. Nickel

How many of the above usually make up battery cathodes?

Accepted Answer

Only two. * Element I is correct: Cobalt is commonly used in cathodes of batteries like Lithium Cobalt Oxide (LCO) and NMC (Nickel Manganese Cobalt) to improve energy density and battery life. * Element II is incorrect: Graphite is the most common material used in the anodes, not the cathodes, of lithium-ion batteries. * Element III is correct: Lithium is present in both cathodes and electrolytes, forming compounds like $LiCoO_{2}$ or $LiFePO_{4}$ in the cathode. * Element IV is correct: Nickel is used in cathodes (like NMC and NCA) to enhance energy density and storage capacity. * Therefore, three elements usually make up battery cathodes.

Question 4

Consider the following substances:
I. Ethanol
II. Nitroglycerine
III. Urea

Coal gasification technology can be used in the production of how many of them?

Accepted Answer

Only one. * Coal gasification converts coal into syngas (CO and $H_2$), which acts as a feedstock for chemical and fuel production. * Option 1 is correct: Syngas from coal gasification can be fermented using specialized anaerobic microorganisms to synthesize ethanol. * Option 2 is incorrect: Nitroglycerine is a vasodilatory drug used primarily to relieve anginal chest pain and is not produced using coal gasification technology. * Option 3 is correct: Coal gasification can be used to produce ammonia, which is then utilized to manufacture urea fertilizers (e.g., the integrated coal gasification-based urea plant at Talcher, Odisha). * Therefore, coal gasification can be used to produce two of the substances.

Question 5

Consider the following statements:
I. No virus can survive in ocean waters.
II. No virus can infect bacteria.
III. No virus can change the cellular transcriptional activity in host cells.

How many of the statements given above are correct?

Accepted Answer

All the three. * Statement I is incorrect: Viruses are highly abundant and active in ocean waters; marine viruses (especially bacteriophages) are the most numerous biological entities in the ocean and can survive in seawater for extended periods. * Statement II is incorrect: Bacteriophages are viruses that specifically infect, replicate within, and kill bacterial cells. * Statement III is incorrect: Viruses regularly manipulate the host's gene expression and cell transcriptional machinery upon infection to favor viral replication and block host defenses. * Therefore, none of the statements are correct.

Question 6

Consider the following space missions:
I. Axiom-4
II. SpaDeX
III. Gaganyaan

How many of the space missions given above encourage and support micro-gravity research?

Accepted Answer

Only two. * Mission I supports research: Axiom-4 is a private mission to the ISS that carries and supports microgravity research experiments related to materials science, medicine, and biology. * Mission II supports research: SpaDeX (Space Docking Experiment) is an Indian mission evaluating autonomous docking, where microgravity environmental effects are actively studied. * Mission III supports research: Gaganyaan is India's crewed spaceflight program where executing microgravity research in life sciences and space medicine is a primary objective.

Question 7

Consider the following:
1. Battery storage
2. Biomass generators
3. Fuel cells
4. Rooftop solar photovoltaic units

How many of the above are considered "Distributed Energy Resources"?

Accepted Answer

Only three. * Items 1, 2, 3, and 4 are correct: Distributed Energy Resources (DERs) include any small-scale, decentralized technologies or devices that can produce, store, or manage electricity situated close to the consumer's end of the meter. * This classification covers rooftop solar photovoltaic arrays, localized small wind turbines, biomass generators, fuel cells, and micro-scale battery storage units. Thus, all four are DERs.

Question 8

Consider the following activities:
1. Tracking the migration of animals
2. Identification of narcotics on passengers at airports or in aircraft
3. Monitoring of precipitation

In how many of the above activities can the radars be used?

Accepted Answer

Only one. * Activity 1 is incorrect: Conventional airport security checkpoints utilize X-ray transmission systems, millimeter-wave scanners, or chemical trace detectors to uncover narcotics and hidden materials on passengers, rather than standard long-wave radar trackers. * Activity 2 is correct: Specialized Doppler weather radars are widely deployed by meteorological departments to monitor precipitation density, map storms, and track rainfall patterns. * Activity 3 is correct: Radar systems are valuable tools used by wildlife researchers to map, track, and examine the migration speeds, flight altitudes, and velocities of flocks of birds or animals across distances. * Therefore, radars are used in exactly two activities.

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