DSSSB TGT & PGT Computer Science General Science PYQ (Part 3): 150 Questions with Revision Notes (2014–2025)

Curated specifically for DSSSB TGT Computer Science (DOE / NDMC), PGT Computer Science, and General Paper 1 (Section A: General Awareness).

📌 Complete 450-Question DSSSB General Science Master Series:

Part 1 Practice Questions 1–150 (Optics, Everyday Chem, Cell Biology) → Part 2 Practice Questions 151–300 (Electronics, Organic, Genetics, Space) → Current Part 3: Questions 301–450 (Thermodynamics, Green Energy, Immunology, Nutrition)

💡 Quick Revision First: Before starting your 20-minute CBT timer below, read through the Topic-Wise Short Notes & Scientific Glossary. These summary cards contain the exact repeated facts asked in DSSSB Paper 1 from 2014 to 2025.

📖 Topic-Wise Revision Notes & Essential Terms (Part 3)

Select a category below to revise high-yield facts before attempting the quiz:

🔥 Heat, Thermodynamics & Wave Mechanics

Core Concepts:

Anomalous Expansion of Water: Water exhibits minimum volume and maximum density at 4°C ($1\text{ g/cm}^3$). This enables aquatic marine life to survive under frozen lakes in winter.
Heat Transfer Modes: Conduction (solids via molecular collisions), Convection (fluids via actual density-driven mass motion), Radiation (electromagnetic waves requiring no material medium).
Doppler Effect: Apparent change in frequency/pitch of a sound wave when the source and observer move relative to each other.
Audible vs Ultrasonic Frequency: Human ear hears $20\text{ Hz}$ to $20,000\text{ Hz}$. Sounds below $20\text{ Hz}$ are Infrasonic (elephants, earthquakes); above $20\text{ kHz}$ are Ultrasonic (bats, SONAR, ultrasound imaging).

Latent Heat: Heat energy absorbed or released during a phase change without altering temperature (e.g., Latent Heat of Vaporization).

Absolute Zero: $0\text{ Kelvin}$ or $-273.15^\circ\text{C}$, the theoretical point where all classical molecular motion ceases.

Total Internal Reflection: Occurs when light travels from a denser to rarer medium at an angle exceeding the critical angle.

Mach Number: Ratio of the speed of an object moving through a fluid to the local speed of sound ($>1$ is Supersonic).

🌿 Environmental Chemistry, Smog & Green Energy

Core Concepts:

Acid Rain: Caused primarily by emissions of Sulfur dioxide ($SO_2$) and Nitrogen oxides ($NO_x$) reacting with atmospheric moisture to form Sulfuric ($H_2SO_4$) and Nitric ($HNO_3$) acids (pH drops below $5.6$).
Photochemical Smog: Formed on sunny days when sunlight reacts with $NO_x$ and volatile organic compounds (VOCs). Main toxic oxidants are Ozone ($O_3$) and Peroxyacetyl Nitrate (PAN).
CNG vs LPG Composition: Compressed Natural Gas (CNG) is predominantly Methane ($CH_4$). Liquefied Petroleum Gas (LPG) consists primarily of Propane ($C_3H_8$) and Butane ($C_4H_{10}$), scented with ethyl mercaptan.
Solar Cells (Photovoltaics): Rely on the photovoltaic effect using high-purity crystalline silicon wafers to directly convert photons into direct current (DC).

BOD (Biochemical Oxygen Demand): Measure of organic water pollution; high BOD indicates low dissolved oxygen and polluted water.

Greenhouse Effect: Retention of infrared radiation by gases like $CO_2$, $CH_4$, $N_2O$, and water vapor.

Fly Ash: Fine particulate residue generated from pulverized coal combustion in thermal power stations, used in Portland cement.

Ethyl Mercaptan: Odorous sulfur compound intentionally added to household LPG cylinders to detect gas leaks.

🦠 Microbiology, Immunology & Vaccines

Core Concepts:

Bacterial vs Viral Pathogens: Tuberculosis (Mycobacterium tuberculosis), Typhoid (Salmonella typhi), and Cholera (Vibrio cholerae) are bacterial. Rabies, Polio, Dengue, and Influenza are viral.
Antibiotics: Substances derived from microorganisms that kill or inhibit bacteria (e.g., Penicillin targeting bacterial peptidoglycan cell walls). Antibiotics have zero efficacy against viruses.
Vaccine Types: Live-attenuated (OPV, BCG), Inactivated/Killed (Covaxin, Salk Polio), Toxoids (Tetanus, Diphtheria), mRNA vaccines (Pfizer/Moderna COVID-19).
Active vs Passive Immunity: Active immunity is built via exposure to antigens/vaccination (long-lasting memory cells). Passive immunity involves direct antibody transfer (e.g., colostrum mother-to-child or antivenom).

BCG Vaccine: Bacille Calmette-Guérin, given universally at birth for protection against Tuberculosis.

Interferons: Antiviral proteins released by virus-infected host cells to protect uninfected neighboring cells.

Colostrum: First mother's milk rich in secretory Immunoglobulin A (IgA) providing newborn passive immunity.

Fermentation: Anaerobic breakdown of sugars by yeast (Saccharomyces cerevisiae) into ethanol and $CO_2$.

🥗 Nutrition, Vitamins & Metabolic Disorders

Core Concepts:

Fat-Soluble vs Water-Soluble Vitamins: Vitamins A, D, E, and K are fat-soluble (stored in liver and adipose tissues). Vitamins B-Complex and C are water-soluble (must be replenished regularly through diet).
Protein Energy Malnutrition (PEM): Kwashiorkor is caused specifically by protein deficiency in the presence of adequate calories (characterized by edema/potbelly). Marasmus is caused by total deficiency of both proteins and calories (wasting).
Blood Clotting Cascade: Requires Vitamin K (for prothrombin synthesis in liver) and Calcium ions ($Ca^{2+}$) to convert fibrinogen into insoluble fibrin mesh.
Enzyme Properties: Biological biocatalysts predominantly made of globular proteins that lower the activation energy of chemical reactions without being consumed.

Vitamin B1 (Thiamine): Deficiency causes Beriberi (cardiovascular or neurological damage).

Vitamin B12 (Cyanocobalamin): Contains Cobalt; deficiency causes Pernicious Anemia.

Rickets: Softening and bowing of bones in growing children due to Vitamin D / Calcium deficiency.

Pepsin: Stomach protease enzyme activated by Hydrochloric Acid ($HCl$) at acidic pH (~1.5 to 2.0).

🔬 Famous Scientific Discoveries & Inventions

Core Concepts:

X-Rays: Discovered by Wilhelm Conrad Röntgen in 1895, earning the first ever Nobel Prize in Physics (1901).
Natural Radioactivity: Discovered by Henri Becquerel (1896); Pierre and Marie Curie later isolated Polonium and Radium.
Vaccination Pioneer: Edward Jenner developed the first successful smallpox vaccine in 1796 using cowpox pustules.
Electron Discovery: Discovered by J.J. Thomson (1897) using the Cathode Ray Tube experiment, demonstrating that atoms are divisible.

Electron Microscope: Invented by Ernst Ruska and Max Knoll (1931), utilizing electron beams for up to 2,000,000x magnification.

Dynamite: Invented by Alfred Nobel in 1867 by stabilizing liquid nitroglycerin using kieselguhr.

Raman Effect: Inelastic scattering of light photons discovered by Sir C.V. Raman (Feb 28, 1928, celebrated as National Science Day).

Periodic Table: Formulated systematically by Dmitri Mendeleev based on atomic masses (modern form arranged by Henry Moseley by atomic numbers).

DSSSB CBT PART 3 General Science PYQs (Q301 to Q450)

Time Remaining: 20:00

Heat, Thermodynamics & Waves Question 301 of 450

DSSSB TGT CS 2021 Repeated 4 Times

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Answered: 0

Unanswered: 150

Marked: 0

Crucial Concepts Tested in DSSSB TGT Computer Science Part 3

Part 3 covers physical thermodynamics, biological catalysts, and environmental systems. Below is an overview of recurrent themes across 2014–2025:

Topic	High-Frequency DSSSB Questions	Frequency in Exam
Thermodynamics & Heat	Maximum density of water at 4°C, latent heat of fusion vs vaporization, vacuum in thermos flasks, sound speed in solid/liquid/gas.	Repeated 8+ times
Smog & Green Energy	Acid rain precursors ($SO_2$ and $NO_2$), Photochemical smog components (Ozone, PAN), CNG composition, Mercaptan in LPG.	Repeated 6+ times
Immunology & Vaccines	BCG vaccine for TB, Edward Jenner cowpox discovery, lack of antibiotic action on viruses, active vs passive immunity.	Repeated 7+ times
Vitamins & Malnutrition	Cobalt in Vitamin B12, Vitamin K in prothrombin synthesis, difference between Kwashiorkor and Marasmus.	Repeated 9+ times

Frequently Asked Questions (DSSSB General Science Part 3)

1. Where can I find Part 1 and Part 2 of this General Science PYQ series?

You can practice both previous sets directly from these links:
• General Science Part 1 (Questions 1 to 150)
• General Science Part 2 (Questions 151 to 300)

2. At what temperature does water exhibit its highest density?

Water reaches its maximum density of $1.0\text{ g/cm}^3$ (or $1000\text{ kg/m}^3$) at exactly 4°C. Due to this anomalous expansion, ice forms on top of water bodies while water underneath stays liquid at 4°C, sustaining marine life in freezing weather.

3. What is the fundamental difference between Kwashiorkor and Marasmus?

Kwashiorkor is caused by a severe deficiency of dietary protein despite receiving adequate calories (leading to swollen bellies/edema and fatty liver). Marasmus is caused by overall starvation (severe deficiency of both proteins and calories), leading to profound muscle wasting and emaciation without edema.

4. Why do antibiotics have no effect on viral infections like common cold or influenza?

Antibiotics specifically target bacterial cellular structures and pathways (such as cell wall synthesis, bacterial ribosomes, or bacterial DNA gyrase). Viruses lack cellular walls, ribosomes, and independent metabolic pathways, replicating only inside host cells, rendering antibiotics ineffective.