Sources of Energy PYQs – Physics, SSC & Railway

Correct Answer:
Correct Answer: Option 2 – High pressure and absence of air for long periods
Explanation:
Petroleum forms from dead marine organisms (plankton, algae) that get buried under layers of sediment on the sea floor. Over millions of years, subjected tohigh pressure, high temperature, and absence of oxygen/air (anaerobic conditions), their remains slowly transform into petroleum and natural gas.
Important Facts:
• Petroleum and natural gas are called fossil fuels because they form from fossilized remains of ancient organisms.
• This is a very slow process taking millions of years, which is why fossil fuels are non-renewable.
• Presence of oxygen/air would cause decomposition rather than fossilization into petroleum.

Correct Answer:
Correct Answer: Option 3 – Their formation happens through slow chemical and physical changes
Explanation:
Coal and petroleum arefossil fuelsformed from the remains of dead plants and animals (organic matter) buried deep under the Earth's crust. Over millions of years, this organic matter undergoes extremelyslow chemical and physical transformations— subjected to high pressure, high temperature, and the absence of oxygen (anaerobic decomposition) — gradually converting it into coal (from plant matter) or petroleum (from marine organisms). This is why these are called non-renewable resources; they cannot be replenished quickly.

Correct Answer:
Correct Answer: Option 4 – Water and volatile substances are lost during coal formation
Explanation:
Coal forms over millions of years from buried plant material under heat and pressure (a process called coalification). During this process, water and volatile compounds (like methane and other gases) are progressively driven off, leaving behind a residue increasingly concentrated in carbon.
Important Facts:
• The coalification sequence (increasing carbon content) is: peat → lignite → bituminous coal → anthracite.
• Coal is a fossil fuel formed from decayed plant matter (largely from the Carboniferous period).

Correct Answer:
Option 1 – millions
Explanation:
Coal is a fossil fuel formed from the remains of trees, ferns, and other plants that were buried under layers of sedimentmillions of years agoand subjected to heat and pressure over a very long geological time scale (a process called carbonization).
Important Facts:
• Coal formation began roughly 300+ million years ago during the Carboniferous period.
• Petroleum and natural gas are also fossil fuels formed over millions of years from organic remains.
Correct Answer: Option 1 – millions

National Hydrogen Mission
India's National Green Hydrogen Mission framework is drafted and administered by theMinistry of New and Renewable Energy (MNRE), the nodal ministry for renewable energy policy including green hydrogen, confirmed by the official MNRE/NGHM portal and government sources.
Correct Answer: Ministry of New and Renewable Energy

Assertion and Reason: formation of coal
Assertion (A): Coal was formed from trees and plants buried under the earth millions of years ago — this is a true, well-established geological fact.
Reason (R): Over millions of years, under high heat and pressure, the buried plant remains underwent slow carbonization to form coal — this is also true and correctly explains how (A) happened.
Since R correctly explains the process described in A, both are true and R is the correct explanation of A.
Correct Answer: Both A and R are true, and R is the correct explanation of A.

Solar Energy Spectrum
The Sun's radiation reaching Earth's surface is dominated by thevisible lightportion of the electromagnetic spectrum, which carries the greatest fraction of solar energy (with the remainder mostly in infrared and a small part UV).
Solar panels are designed primarily to capture this visible-light-dominant energy for electricity generation.
Correct Answer: Visible light

Solar Panel Efficiency and Sun Angle
In the early morning, the Sun is low on the horizon, so sunlight strikes the solar panel at a low angle (large angle of incidence).
• The same amount of solar energy is spread over a larger effective area, and light also travels through a longer path of atmosphere, both reducing the intensity reaching the panel.
• Lower intensity of incident light directly means less energy converted by the panel, reducing efficiency.
• The other options are incorrect: light's speed in air does not change with time of day, Earth's rotation does not 'increase' intensity, and wavelength shift is a secondary effect, not the main cause of reduced efficiency.
Correct Answer: Sunlight is less intense at low angle

Answer: Option 2 – Coal, because these conditions favour coal formation from ancient plants.
• Ancient plant remains buried under heat and pressure formcoal.

Answer: Option 3 – Both A and R are true, and R is the correct explanation of A.
• Fossil fuels formed from ancient dead organisms – R correctly explains why coal and petroleum are called fossil fuels.

Answer: Option 1 — A utility-scale solar photovoltaic farm
For maximum renewable, eco-friendly energy, choose asolar PV farm→ Option 1.

Answer: Option 4 – Peat → Lignite → Bituminous → Anthracite.
• Coal forms by increasing carbonisation of buried plant matter:Peat → Lignite (brown coal) → Bituminous → Anthracite(hardest, highest carbon).
• The other sequences reverse this order and are wrong.

Answer: Option 3 — High pressure, high temperature, anaerobic conditions
Petroleum forms from marine organic matter underhigh pressure, high temperature and absence of oxygen (anaerobic)over long periods → Option 3.

Energy Resources Classification:
Exhaustible:Resources that get depleted with use (finite)
Polluting:Resources that emit harmful gases/pollutants
Analysis of Options:
Wind → Renewable, Non-polluting
Biogas → Renewable, Minimal pollution
Solar → Renewable, Non-polluting
Coal →Fossil fuel, Non-renewable, Highly polluting
Coal releases CO₂, SO₂, NOₓ and particulate matter
Answer: Option 4 → Coal

Correct Answer: Thermal energy (Option 4)
Non-conventional (renewable) energy sources are those that are naturally replenished and are alternatives to fossil fuels. Wind energy, solar energy, and tidal energy are all non-conventional renewable energy sources.
Thermal energy (generated by burning fossil fuels like coal, oil, and natural gas in thermal power plants) is a CONVENTIONAL energy source. It is non-renewable, finite, and a major source of pollution and greenhouse gases.
Why others are wrong (i.e., they ARE non-conventional):
- Wind energy: Renewable; generated from wind turbines.
- Solar energy: Renewable; generated from sunlight using solar panels.
- Tidal energy: Renewable; generated from the movement of ocean tides.

Correct Answer: Solar energy — Option (d)
Solar energy is classified as a non-conventional (renewable) energy resource in India. About Energy Classification in India: Conventional Energy Resources (Traditional): Fossil fuels — formed over millions of years from ancient organisms; Non- renewable (finite supplies); Petroleum (crude oil): Refined into petrol, diesel, kerosene; India imports about 85% of its crude oil requirement; Natural Gas: Used for cooking (LPG), power generation, fertilizers; Coal: India has the world's 4th largest coal reserves; Primary source for electricity generation in India (about 70%); Nuclear energy: Uses uranium; finite resource; All three options (a), (b), (c) are conventional energy resources; Non-Conventional (Renewable) Energy Resources: Derived from natural processes that are continuously replenished; Solar Energy: Energy from sunlight; Captured by solar panels (photovoltaic cells) or solar thermal systems; India's target: 500 GW renewable energy by 2030; India has one of the world's largest solar power programs; Solar energy is abundant in India (due to tropical location); Wind Energy: Energy from wind; India has significant wind energy capacity; Hydropower (small scale): Energy from flowing water; Tidal Energy: Energy from tides; Geothermal Energy: Heat from the earth's interior; Biomass Energy: Energy from organic materials; About India's Renewable Energy Push: International Solar Alliance (ISA): Founded by India and France in 2015; India is the host country; Goal: Promote solar energy globally; India's renewable energy capacity has been growing rapidly.
Option (a) Petroleum — Incorrect: Petroleum is a CONVENTIONAL (fossil fuel) energy resource — NOT non-conventional; it was formed millions of years ago from ancient marine organisms under heat and pressure; petroleum is finite and non-renewable; India imports about 85% of its petroleum requirements; it is classified as a conventional energy resource.
Option (b) Natural gas — Incorrect: Natural gas is a CONVENTIONAL (fossil fuel) energy resource — NOT non-conventional; it is a hydrocarbon gas mixture formed from ancient organic matter decomposed under pressure; it is finite and non-renewable; while it is cleaner than coal and oil, it remains a conventional fossil fuel energy resource.
Option (c) Coal — Incorrect: Coal is a CONVENTIONAL (fossil fuel) energy resource — NOT non-conventional; it is formed from ancient plant matter compressed over millions of years; coal is the most carbon-intensive fossil fuel; India is one of the largest coal producers in the world; it is clearly a conventional energy resource, NOT a non-conventional or renewable one.

Energy Conservation Act, 2001
Enacted to address India's growing energy demand and promote efficient energy use.
Primary Goal:Reduce energy intensity of the Indian economy
Energy intensity = Energy consumed per unit of GDP
Key Features:
• Established Bureau of Energy Efficiency (BEE)
• Mandates energy audits for large industries
• Sets energy consumption norms
Answer: Option 2 → To reduce energy intensity in the Indian economy

Topic: Natural Resources Classification
Non-renewable resources:Cannot be replenished naturally in a short time period. Once exhausted, they are gone forever.
Petroleumis a fossil fuel formed from ancient organic matter over millions of years. It cannot be regenerated quickly.
Renewable resources:Wind, Solar, and Biomass can be replenished naturally and continuously.
Answer: Option 2 → Petroleum

Solution:
•Coalis afossil fuelformed from theremains of ancient plants.
• Millions of years ago, large forests were buried undersoil and sediments, preventing complete decomposition.
• Over time,heat and pressureconverted these plant remains intocoalthrough a process calledcarbonisation.
• Therefore, coal is mainly formed fromlayers of dead plants compressed for millions of years.

Correct Answer: 1 (2030)
India has set an ambitious target to scale up its wind energy capacity from approximately 42 GW to 140 GW by 2030, as part of its broader renewable energy targets. India's overall renewable energy target is 500 GW of non-fossil fuel-based power capacity by 2030, in line with its commitments under the Paris Agreement and Net Zero goals.
Option 2 (2035) is incorrect.
Option 3 (2040) is incorrect.
Option 4 (2050) is incorrect.

The National Solar Mission (Jawaharlal Nehru National Solar Mission) is one of eight national missions under the National Action Plan on Climate Change (NAPCC), launched in 2008 by the Government of India to address climate change challenges. Option 2 is correct.
Option 1 is wrong: Make in India (2014) is a manufacturing and FDI promotion initiative; it does not encompass national climate missions.
Option 3 is wrong: AMRUT (Atal Mission for Rejuvenation and Urban Transformation) focuses on urban infrastructure like water supply and sewerage, not solar energy.
Option 4 is wrong: Swachh Bharat Abhiyan is a cleanliness and sanitation mission; it is not related to solar energy or the NAPCC framework.

The correct answer is Electric buses . Zero-emission transport refers to vehicles that do not release harmful pollutants or greenhouse gases from their exhaust. Among the listed options, electric buses operate solely on electricity stored in batteries and therefore do not emit carbon dioxide (CO₂), nitrogen oxides (NOₓ), or particulate matter during operation. They are becoming a preferred choice in many countries for sustainable public transport because they significantly reduce urban air pollution and dependence on fossil fuels. Petrol cars and diesel buses, on the other hand, release a large amount of greenhouse gases, while hybrid vehicles still rely partly on fossil fuels, so they are not completely zero-emission. India, under the FAME (Faster Adoption and Manufacturing of Electric Vehicles) scheme, has been actively promoting electric buses to meet its clean energy and climate goals.

Correct Answer: 1 (Option 1)
The International Solar Alliance (ISA) aims to mobilize USD 1 trillion in solar energy investments by 2030. The ISA was launched jointly by India and France in 2015 at COP21 in Paris. It works to increase solar energy use in member countries, especially those between the Tropics of Cancer and Capricorn.
Why others are wrong:
Option 2 - 5 trillion: The ISA target is 1 trillion USD, not 5 trillion.
Option 3 - 3 trillion: Incorrect amount.
Option 4 - 4 trillion: Incorrect; the official ISA target is 1 trillion USD by 2030.

The Government of India has set a target of achieving 140 GW of wind power capacity by 2030 as part of its renewable energy goals. India aims for 500 GW of non-fossil fuel-based energy capacity by 2030. Wind energy is a key pillar of India's clean energy transition. Options 1, 2, and 4 do not match the official target year.

SATAT (Sustainable Alternative Towards Affordable Transportation) is an initiative under the Ministry of Petroleum & Natural Gas, Government of India. It aims to promote Compressed Biogas (CBG) as an affordable, clean transportation fuel. The scheme provides support for setting up CBG production plants and helps create a market for CBG in the automotive sector. Why other options are wrong: Option 2 - Ministry of Housing & Urban Affairs: Deals with urban planning and housing, not fuel/transportation initiatives. Option 3 - Ministry of Urban Development: Not the ministry overseeing SATAT. Option 4 - Ministry of Home Affairs: Handles internal security and border management, not related to SATAT.

PM-KUSUM aims to provide energy and water security to farmers by encouraging the installation of solar pumps and grid-connected solar power plants in rural areas.
It has three components: solar pumps, solarisation of existing pumps, and decentralised solar plants.

Statement 1 is correct: solar power is renewable, has low operational costs and minimal direct emissions.
Statement 2 is correct: the Kamuthi Solar Power Project in Tamil Nadu has a capacity of 648 MW, making it one of the largest single-location solar plants in India.

Correct Answer: Option 2 – Availability of flat, arid, and sparsely populated land with high insolation
For utility-scale solar farms, the most critical geographical factor balancing land acquisition issues, environmental impact, and energy output is the availability of flat, arid, sparsely populated land with high solar insolation (solar radiation intensity). This combination: (a) minimizes land acquisition conflicts (sparse population, low agricultural value), (b) reduces environmental impact (arid lands have lower biodiversity sensitivity than forests/wetlands), (c) maximizes energy output (high insolation = more solar radiation per unit area). India's Rajasthan, Gujarat, and Ladakh fit this profile — the Bhadla Solar Park (Rajasthan) is the world's largest.
Option 1 (Seismically active zones): Seismic activity poses structural risk to solar infrastructure; geothermal energy is a separate technology — not integrated with solar farms.
Option 3 (Proximity to urban centers): While proximity reduces transmission losses, land near urban centers is expensive and scarce — worsening land acquisition challenges.
Option 4 (Water resources for cleaning): Panel cleaning requires some water, but this is a minor operational consideration, not the most critical geographical factor for siting.

Correct Answer: Option 3 – They generate electricity using sunlight
Solar panels (photovoltaic cells) convert sunlight (solar radiation) directly into electricity through the photovoltaic effect. Silicon-based solar cells absorb photons from sunlight, which knock electrons free and create an electric current. Key advantages: renewable/inexhaustible energy source, zero emissions during operation, low operating costs, minimal maintenance, reduces dependence on fossil fuels, and can be deployed at any scale (rooftop to utility). India's solar capacity has grown from ~3.7 GW (2014) to over 85 GW (2024).
Option 1 (They cause air pollution): The opposite is true — solar panels produce no air pollutants during operation. Manufacturing involves some carbon footprint, but operational emissions are zero.
Option 2 (They require fuel to operate): Solar panels require only sunlight to operate — no fuel costs. This is one of their major economic advantages.
Option 4 (They use coal for energy): Solar panels use solar radiation, not coal. Coal is a fossil fuel used in thermal power plants — the opposite of solar energy.

Correct Answer: Option 1 – Coal
Coal is a fossil fuel formed from organic matter over millions of years through heat and pressure. Once extracted and used, it cannot be replenished in a human timescale, making it a non-renewable resource.
Option 2 (Wind energy): Wind is a renewable resource; it is continuously replenished by atmospheric processes driven by solar energy.
Option 3 (Tidal energy): Tidal energy is renewable, generated by the gravitational pull of the Moon and Sun on Earth's oceans.
Option 4 (Solar energy): Solar energy is a perpetually renewable resource derived from the Sun's radiation.

Correct Answer: Option 3 – Natural Gas
Natural Gas is a fossil fuel that takes millions of years to form from decomposed organic matter under extreme heat and pressure. Once consumed, it cannot be replenished within any meaningful human timescale, making it a non-renewable energy source.
Option 1 (Wind): A renewable energy source; wind is continuously available and replenished by atmospheric processes.
Option 2 (Solar): A renewable energy source; solar radiation is continuously available.
Option 4 (Hydroelectric): A renewable energy source; water in rivers is continuously replenished by the water cycle driven by solar energy.