General Knowledge (Mixed)

A hydrometer is an instrument specifically designed to measure the density (or specific gravity) of liquids, floating higher in denser liquids and lower in less dense ones based on Archimedes' principle. It is commonly used to test battery fluid, urine specific gravity, and alcohol concentration in brewing.

Water is the only common substance that naturally exists in all three states of matter - solid (ice), liquid (water), and gas (water vapor) at Earth's surface temperatures. Ice is solid water, not a separate substance.

Blood pressure varies during sleep cycles and can fluctuate with body movements, REM sleep, and autonomic nervous system activity. While it generally decreases during sleep compared to wakefulness, it doesn't remain perfectly constant.

Hypertension (high blood pressure) is called the 'silent killer' because it can damage your heart, kidneys, brain, and arteries for years without causing any noticeable symptoms until serious complications like heart attack or stroke occur.

Marble is a metamorphic rock formed when limestone is subjected to high heat and pressure deep underground, causing the calcite in limestone to recrystallize into larger, interlocking crystals.

Gas has the lowest density among the options listed. Gases have molecules far apart with minimal attraction, resulting in very low mass per unit volume compared to liquids (water) and solids (sand, dust).

Akali Phoola Singh served as the chief commander of Maharaja Ranjit Singh's army and was a trusted military advisor who led several successful campaigns.

One pound equals approximately 453.592 grams. The question asks for the equivalent weight in grams, and 453 gms is the closest and most accurate option provided.

Carbon monoxide is a toxic gas that pollutes the air and is harmful to human health. Oxygen, nitrogen, and hydrogen are natural components of air and are not considered pollutants in their normal atmospheric concentrations.

Marie Curie, along with her husband Pierre Curie, discovered radium in 1898. She was a pioneering physicist and chemist who conducted extensive research on radioactivity.

Carbon dioxide has a molar mass of 44 g/mol compared to air's average of 29 g/mol, making it about 1.5 times heavier than air. This is why CO2 settles in low-lying areas and can displace oxygen.

John Logie Baird is credited with inventing the first practical television system in the 1920s. He demonstrated the first working television and was a pioneer in the development of television technology.

Phosphorus is a nonmetallic element located in Group 15 of the periodic table. It exists in several allotropic forms (white, red, black) and is essential for life, being a component of DNA, RNA, and ATP.

Sriharikota (SDSC-SHAR) is India's primary satellite launch station, located in Andhra Pradesh. It is where most ISRO missions, including Chandrayaan and Mangalyaan, were launched. Ahmedabad (SAC) and Bangalore (URSC) are ISRO centers but not launch sites.

Sound travels fastest in solids because their particles are closely packed, allowing faster vibration transmission. Steel, being a solid with high elasticity, transmits sound much faster (~5000 m/s) than liquids or gases. Water and alcohol are liquids where sound travels slower.

James Watt made crucial improvements to the steam engine design in the late 18th century, dramatically improving efficiency and making it practical for industrial use. While Thomas Newcomen built an earlier steam engine, Watt's innovations (separate condenser, parallel motion) are why he's commonly credited in popular knowledge.

Alexander Fleming discovered penicillin in 1928 when he noticed that mold (Penicillium notatum) had antibacterial properties. This accidental discovery at St. Mary's Hospital in London revolutionized medicine and earned Fleming the Nobel Prize. Louis Pasteur contributed to germ theory and pasteurization, while C.V. Raman worked in physics.

Dehydration is the process of removing water from substances. In biological contexts, it means harmful water loss from the body. In food preservation, it means removing moisture to prevent bacterial growth. The suffix '-tion' indicates a removal process.

Microbiology is the scientific study of microorganisms including bacteria, viruses, fungi, and protozoa. Anatomy studies body structure, bionics applies biological systems to engineering, and ecology studies organism-environment interactions. The prefix 'micro-' indicates small organisms.

Lemons contain citric acid (C6H8O7), which gives them their characteristic sour taste. Citric acid is a natural preservative found in citrus fruits. Oxalic acid is in spinach (causes metallic taste), acetic acid is in vinegar. Citric acid is the correct answer.

Lala Hardayal was a prominent Indian nationalist and founding member of the Ghadar Party (1913), which aimed to overthrow British rule through armed revolution. The party operated primarily among Indian immigrants in North America. INA was formed later (1942), and Naujawan Sabha was a different organization.

Jaundice is caused by liver dysfunction when the liver cannot process bilirubin properly, leading to its accumulation. This causes yellowing of skin and eyes (sclera). While jaundice affects eyes and skin visibly, it originates from liver disease or bile duct obstruction. Urine may darken but jaundice is not a disease of urine.

Copper is an excellent conductor of electricity due to its free electrons that can move easily through the metal lattice. Rubber, wood, and glass are insulators with high electrical resistance. Copper's conductivity (59.6 x 10^6 S/m) makes it standard for electrical wiring.