General Science - MCQ Practice Questions
General Science in SSC, railway and state exams stays at school level, which makes it one of the few sections where full marks are realistic. Practice covers physics fundamentals such as motion, light and electricity, chemistry basics including elements and compounds, and biology topics like the human body, nutrition and diseases. Answers stay at the depth the paper actually uses instead of drifting into degree level theory.
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The concept of 'Ecological Footprint' measures which of the following?
Understanding:
We need to identify what the term 'Ecological Footprint' specifically measures.
Step 1: Definition of Ecological Footprint
The Ecological Footprint is a metric developed by Mathis Wackernagel and William Rees in the early 1990s. It quantifies the amount of biologically productive land and water area that a human population requires to produce the resources it consumes and to absorb the waste it generates, using prevailing technology.
Step 2: Eliminate incorrect options
Step 3: Confirm correct answer
The ecological footprint is a comprehensive sustainability indicator encompassing food, water, energy, land for waste absorption, and built-up land — expressed in global hectares (gha).
Answer:
Ecological Footprint measures the biologically productive land and water needed to sustain resource use and absorb waste for a given population.
Which of the following is classified as a 'Hotspot of Biodiversity' in India?
Understanding:
We need to identify which region in India is officially recognised as a Biodiversity Hotspot.
Step 1: What is a Biodiversity Hotspot?
A biodiversity hotspot is a biogeographic region that is both a significant reservoir of biodiversity and is threatened by human habitation. To qualify, a region must have at least 1,500 endemic vascular plant species and have lost at least 70% of its original habitat.
Step 2: India's Biodiversity Hotspots
India has four recognised biodiversity hotspots:
1. Western Ghats
2. Eastern Himalayas (Indo-Burma region)
3. Sundaland (includes Nicobar Islands)
4. Indo-Burma region
Step 3: Evaluate the options
Answer:
The Western Ghats is a recognised Biodiversity Hotspot in India.
Quick Tip:
India hosts 4 of the world's 36 biodiversity hotspots. The Western Ghats alone is home to over 5,000 species of flowering plants, 139 mammal species, 508 bird species, and 179 amphibian species.
Which of the following international agreements specifically deals with the control of trade in endangered species of wild fauna and flora?
Understanding:
We need to match the international agreement that specifically regulates trade in endangered species.
Step 1: Review each agreement
Step 2: Identify the correct agreement
CITES directly addresses the issue of trade in endangered species by listing species in three appendices based on their level of protection needed and controlling or banning their international trade accordingly.
Answer:
CITES is the international agreement that controls trade in endangered species of wild fauna and flora.
Quick Tip:
CITES currently protects over 38,000 species of animals and plants. India is a signatory and has listed species such as tigers, elephants, and rhinos under its provisions.
Eutrophication of water bodies is primarily caused by an excess of which of the following nutrients?
Understanding:
We need to identify the nutrients primarily responsible for eutrophication of water bodies.
Step 1: What is Eutrophication?
Eutrophication is the process by which a water body becomes overly enriched with nutrients, leading to excessive growth of algae and aquatic plants (algal blooms). This reduces dissolved oxygen in the water, creating dead zones and harming aquatic life.
Step 2: Primary nutrients responsible
Nitrogen (N) and Phosphorus (P) are the two key limiting nutrients that trigger eutrophication. They enter water bodies mainly through:
Step 3: Eliminate other options
Answer:
Eutrophication is primarily caused by excess nitrogen and phosphorus in water bodies.
Quick Tip:
The process of oxygen depletion following an algal bloom is called hypoxia. The dead zones formed in water bodies due to eutrophication are well documented in lakes such as Dal Lake (Kashmir) and parts of the Baltic Sea.
Which of the following correctly defines 'Biomagnification'?
Understanding:
We need to identify the correct definition of 'Biomagnification' from the given options.
Step 1: Define Biomagnification
Biomagnification (also called biological magnification or bioamplification) refers to the progressive increase in the concentration of a toxic substance — such as DDT, mercury, or PCBs — in organisms at each successive trophic level of a food chain. The substance is not metabolised or excreted efficiently, so it accumulates in body fat or tissues.
Step 2: Typical example
In the DDT example:
This caused thinning of eggshells in raptors, leading to population declines.
Step 3: Eliminate incorrect options
Answer:
Biomagnification is the increase in concentration of toxic substances at successively higher trophic levels in a food chain.
Quick Tip:
Biomagnification is different from bioaccumulation. Bioaccumulation refers to the build-up of a substance within a single organism, while biomagnification refers to the increase in concentration across trophic levels.
The 'Red Data Book' maintained by the International Union for Conservation of Nature (IUCN) is used for which of the following purposes?
Understanding:
We need to identify the purpose of the IUCN Red Data Book (Red List).
Step 1: What is the IUCN Red List?
The IUCN Red List of Threatened Species (commonly called the Red Data Book) is the world's most comprehensive inventory of the conservation status of biological species. It was established in 1964 and classifies species into categories such as:
Step 2: Purpose
The primary purpose is to document the conservation status of threatened species of plants, animals, fungi, and other organisms to guide conservation efforts and policy decisions globally.
Step 3: Eliminate other options
Answer:
The IUCN Red Data Book documents the conservation status of threatened species of plants, animals, and fungi.
Quick Tip:
As of recent assessments, over 42,000 species are listed as threatened with extinction on the IUCN Red List. India's Great Indian Bustard is listed as Critically Endangered.
Which of the following correctly describes the primary cause of 'Acid Rain'?
Understanding:
We need to identify the primary cause of acid rain from the given options.
Step 1: Chemistry of Acid Rain
Acid rain forms when sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) are released into the atmosphere — mainly from burning fossil fuels, vehicle emissions, and industrial processes. These gases react with water vapour, oxygen, and other chemicals in the atmosphere to form sulphuric acid and nitric acid, which fall as acid rain.
Step 2: Key reactions
The main reactions are:
Step 3: pH of acid rain
Normal rain has a pH of about 5.6 (slightly acidic due to dissolved CO₂ forming carbonic acid). Acid rain has a pH below 5.6, sometimes as low as 4 or less.
Step 4: Eliminate incorrect options
Answer:
Acid rain is primarily caused by emissions of sulphur dioxide and nitrogen oxides that react with atmospheric moisture to form sulphuric and nitric acids.
Quick Tip:
Acid rain causes damage to forests, aquatic ecosystems, soil, and heritage structures (such as the Taj Mahal, which has been affected by acid rain from nearby industries).
Which of the following technologies is used in 'Li-Fi' communication systems?
Understanding:
This question asks about the underlying technology used in Li-Fi (Light Fidelity) wireless communication systems.
Step 1: What is Li-Fi?
Li-Fi is a wireless communication technology proposed by Professor Harald Haas in 2011. Unlike Wi-Fi, which uses radio waves, Li-Fi transmits data using visible light emitted by LED bulbs. The light is modulated at very high speeds, imperceptible to the human eye, to encode and transmit data.
Step 2: Why visible light?
LED lights can be switched on and off millions of times per second. This rapid switching forms the basis of data transmission in Li-Fi, enabling speeds potentially far exceeding conventional Wi-Fi.
Step 3: Eliminating other options.
Radio waves are used in Wi-Fi and mobile networks. Infrared is used in TV remotes and some short-range communication, not Li-Fi. Microwave signals are used in radar, satellite, and some broadband communication technologies.
Answer:
Li-Fi uses visible light (from LED sources) to transmit data wirelessly.
Quick Tip:
Li-Fi stands for Light Fidelity — the word 'light' itself is a strong hint that visible light is the medium of communication.
Which of the following is the correct full form of 'GPS' as used in navigation technology?
Understanding:
This question asks for the correct expansion of the abbreviation GPS used in navigation and location-tracking technology.
Step 1: Origin of GPS.
GPS was developed by the United States Department of Defense. It is a satellite-based radio navigation system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth.
Step 2: What each letter stands for.
G — Global, P — Positioning, S — System. The full form is Global Positioning System.
Step 3: Eliminating other options.
None of the other expansions — General Prediction Satellite, Geo-Positional Signal, or Global Precision Sensor — correspond to any recognized technology or standard.
Answer:
The correct full form of GPS is Global Positioning System.
Quick Tip:
India's own regional navigation satellite system is called NavIC (Navigation with Indian Constellation), developed by ISRO as a counterpart to GPS.
Which of the following best describes the function of a 'firewall' in computer networks?
Understanding:
This question asks about the primary function of a firewall in the context of computer network security.
Step 1: Definition of a Firewall.
A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic. It establishes a barrier between a trusted internal network and untrusted external networks such as the Internet, based on a defined set of security rules.
Step 2: What a firewall does NOT do.
A firewall does not speed up connections — that is the role of caching or compression tools. It does not convert digital to analog signals — that is the function of a modem. It does not store backup copies of files — that is the role of backup software or cloud storage.
Step 3: Conclusion.
The core function of a firewall is packet filtering and traffic monitoring based on security policies, making option B the only correct description.
Answer:
A firewall monitors and controls network traffic based on predetermined security rules.
Quick Tip:
Firewalls can be hardware-based, software-based, or both. Most operating systems like Windows come with a built-in software firewall.
Which generation of mobile network technology introduced the concept of 'packet switching' and enabled mobile internet access for the first time?
Understanding:
This question asks which generation of mobile technology first introduced packet switching and mobile internet capability.
Step 1: Understanding 1G.
1G (First Generation) networks, introduced in the 1980s, were analog systems used only for voice calls. They had no data services.
Step 2: Understanding 2G.
2G networks, introduced in the early 1990s (GSM standard), were the first digital mobile networks. They introduced packet switching through GPRS (General Packet Radio Service) and EDGE technologies, enabling limited mobile internet access such as WAP browsing and MMS.
Step 3: Understanding 3G and 4G.
3G provided significantly faster internet speeds and multimedia support, while 4G (LTE) brought broadband-level mobile internet. However, the first introduction of packet switching and mobile internet was with 2G technology.
Step 4: Conclusion.
2G was the first generation to move from circuit switching (used in voice calls) to packet switching for data, enabling mobile internet access.
Answer:
2G was the first mobile network generation to introduce packet switching and mobile internet access.
Quick Tip:
Remember the progression: 1G = Analog voice; 2G = Digital voice + basic internet; 3G = Multimedia internet; 4G = High-speed broadband; 5G = Ultra-low latency + massive connectivity.
Which of the following storage technologies uses 'flash memory' and has no moving mechanical parts?
Understanding:
This question asks which storage device uses flash memory and contains no moving parts.
Step 1: Understanding flash memory.
Flash memory is a type of non-volatile storage that can be electrically erased and reprogrammed. It retains data without a power supply and has no moving parts.
Step 2: Evaluating each option.
Hard Disk Drive (HDD): Uses magnetic platters and a mechanical read/write head — it has moving parts.
Compact Disc (CD) and DVD: Use laser technology to read/write data on optical discs — they have a spinning disc and a moving laser mechanism.
Solid State Drive (SSD): Uses NAND-based flash memory chips. It has no moving parts, is faster, lighter, and more shock-resistant than an HDD.
Step 3: Conclusion.
SSD is the correct answer as it is based entirely on flash memory with no mechanical components.
Answer:
A Solid State Drive (SSD) uses flash memory and has no moving mechanical parts.
Quick Tip:
Because SSDs have no moving parts, they are more durable and faster than HDDs, which is why modern laptops increasingly use SSDs instead of traditional hard drives.
The technology known as 'Bluetooth' primarily operates on which of the following frequency bands?
Understanding:
This question asks about the radio frequency band on which Bluetooth technology operates.
Step 1: Definition of Bluetooth.
Bluetooth is a short-range wireless communication technology standard used to exchange data between fixed and mobile devices over short distances using radio waves.
Step 2: Operating frequency of Bluetooth.
Bluetooth operates in the ISM (Industrial, Scientific and Medical) band at 2.4 GHz, specifically between 2.400 GHz and 2.4835 GHz. It uses frequency-hopping spread spectrum to reduce interference.
Step 3: Context of other frequencies.
900 MHz is used in older GSM mobile networks. 5 GHz is used in Wi-Fi (802.11a/ac/ax). 60 GHz is used in WiGig and millimeter-wave 5G applications. None of these are Bluetooth.
Answer:
Bluetooth operates primarily in the 2.4 GHz frequency band.
Quick Tip:
Both Bluetooth and 2.4 GHz Wi-Fi share the same frequency band, which is why they can sometimes interfere with each other. Bluetooth uses frequency-hopping to minimize this interference.
Which of the following correctly describes 'Artificial Intelligence (AI)' in the context of modern technology?
Understanding:
This question asks for the correct definition of Artificial Intelligence (AI) as it is understood in modern technology.
Step 1: Defining Artificial Intelligence.
Artificial Intelligence refers to the simulation of human intelligence processes — such as learning, reasoning, problem-solving, perception, and language understanding — by computer systems or machines. It encompasses subfields like machine learning, deep learning, natural language processing, and computer vision.
Step 2: Evaluating incorrect options.
Using satellites for communication is the domain of satellite technology and telecommunications — not AI. Designing microchips to increase processor speed falls under semiconductor engineering. Converting analog data to digital is called Analog-to-Digital Conversion (ADC), a signal processing technique.
Step 3: Conclusion.
Option B accurately and completely defines Artificial Intelligence.
Answer:
Artificial Intelligence is the simulation of human intelligence processes by computer systems.
Quick Tip:
AI is the broader concept; Machine Learning (ML) is a subset of AI where systems learn from data; Deep Learning is a subset of ML that uses neural networks inspired by the human brain.
Which of the following technologies forms the backbone of cryptocurrencies like Bitcoin?
Understanding:
This question asks about the fundamental underlying technology that powers cryptocurrencies such as Bitcoin.
Step 1: What is Blockchain?
Blockchain is a distributed ledger technology in which records (called blocks) are linked together and secured using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data, making the chain immutable and transparent.
Step 2: How it relates to Bitcoin.
Bitcoin, introduced in 2009 by the pseudonymous Satoshi Nakamoto, uses blockchain as its underlying technology to record all transactions in a decentralized, peer-to-peer network without the need for a central authority such as a bank.
Step 3: Eliminating other options.
Cloud Computing refers to delivering computing services over the internet. Augmented Reality overlays digital content on the real world. Quantum Computing uses quantum mechanical phenomena to process information — none of these are the backbone of cryptocurrency.
Answer:
Blockchain technology forms the backbone of cryptocurrencies like Bitcoin.
Quick Tip:
Blockchain's key features — decentralization, immutability, and transparency — make it applicable beyond cryptocurrency, including in supply chain management, voting systems, and digital contracts (smart contracts).
Which of the following is the primary function of a 'Router' in a computer network?
Understanding:
This question asks about the primary function that distinguishes a router from other networking devices.
Step 1: What does a Router do?
A router is a networking device that forwards data packets between different computer networks. It operates at the Network Layer (Layer 3) of the OSI model and uses IP addresses to determine the best path for data to travel from source to destination.
Step 2: Distinguishing from similar devices.
A switch connects multiple devices within a single LAN and uses MAC addresses (Layer 2) — this describes a network switch, not a router. An amplifier or repeater regenerates signals — these are physical layer devices. Converting digital signals to light pulses is the function of a media converter or optical transceiver.
Step 3: Conclusion.
The defining function of a router is directing data packets between distinct networks using IP addresses, enabling internet connectivity.
Answer:
A router forwards data packets between different computer networks using IP addresses.
Quick Tip:
A simple memory aid: Switch = connects devices within the same network (LAN); Router = connects different networks together (LAN to WAN/Internet).
The technology 'RFID' is widely used in access cards, library books, and supply chain management. What does RFID stand for?
Understanding:
This question asks for the correct full form of the abbreviation RFID, a technology commonly used in contactless identification and tracking systems.
Step 1: What is RFID?
RFID stands for Radio Frequency Identification. It is a technology that uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID tag contains electronically stored information that can be read by an RFID reader without requiring a direct line of sight or physical contact.
Step 2: Applications of RFID.
RFID is used in contactless smart cards, electronic toll collection (like FASTag in India), inventory management, library book tracking, animal tagging, and passport chips.
Step 3: Eliminating incorrect options.
None of the other expansions — Remote Frequency Identification Device, Rapid File Indexing and Detection, or Real-time Field Integrated Data — represent any recognized technology term or standard.
Answer:
RFID stands for Radio Frequency Identification.
Quick Tip:
FASTag, the electronic toll collection system mandated in India, uses RFID technology. The tag on the vehicle windscreen communicates with readers at toll plazas via radio waves for seamless, cashless toll payment.