Everyday Science

Ethyl Mercaptan is commonly added to LPG cylinders because of its strong, distinctive smell, which helps in detecting gas leaks safely and effectively.

Sonography uses ultrasonic waves, which are sound waves with frequencies higher than the audible range for humans. These waves penetrate the body and reflect off tissues to create images, making option A correct.

Astigmatism is a refractive error caused by an irregular curvature of the cornea or lens, which is corrected using cylindrical lenses that compensate for the uneven curvature. Concave, convex, and spherical lenses do not specifically correct astigmatism.

A photometer is an instrument used to measure the intensity or brightness of light. Therefore, option B, 'Measuring light Intensity,' correctly describes the function of a photometer.

A transistor amplifies weak electrical signals into stronger signals, making option B correct. It is commonly used as an amplifier in electronic circuits.

Photolysis is the process of splitting water molecules using light energy, typically occurring in photosynthesis. This distinguishes it from electrolysis (using electric current), radiolysis (using radiation), and thermolysis (using heat).

The ocean appears blue primarily because water absorbs colors in the red part of the light spectrum more strongly than blue. Blue light is scattered and reflected back to our eyes by water molecules and tiny particles in the water. This scattering of blue light within the water is the main reason the ocean looks blue, not just reflection from the surface. Reflection of the sky can contribute but is not the primary cause.

Reverse osmosis is a widely used method for water purification, where water is forced through a semipermeable membrane to remove impurities. Osmosis, cytolysis, and turgor pressure are biological or physical processes not used for purifying water.

The cover of a capsule is typically made of gelatin, which is a common material used to form the outer shell of capsules in pharmaceuticals and supplements. This material is preferred because it is digestible and can encapsulate the contents securely.

Cadmium is a stable, non-radioactive element, whereas thorium, radium, and uranium are all naturally radioactive elements. Therefore, cadmium is the correct answer as it is not radioactive.

The term 'atom' was first coined by the ancient Greek philosopher Democritus, who proposed that matter is composed of indivisible particles called atoms. This is historically accurate and well-established in science history.

Lockjaw, or difficulty in opening the mouth, is a classic symptom of tetanus, caused by a bacterial toxin affecting the nervous system. The other options do not typically present with lockjaw.

Michael Faraday is credited with inventing the electric motor in the early 1820s by demonstrating electromagnetic rotation, which laid the foundation for electric motor technology.

Jonas Salk developed the first effective polio vaccine in the early 1950s, which significantly reduced polio incidence worldwide. The other options are unrelated to the polio vaccine discovery.

The study of aging is called Gerontology, which focuses on the biological, psychological, and social aspects of aging. The other options are unrelated or misspelled terms.

A transmission channel is the medium that carries the signal from the source to the destination, enabling communication between devices. The transmitter sends the signal, and the receiver receives it, but the medium itself is the transmission channel.

Joseph Lister pioneered antiseptic surgery in 1865 by introducing the use of carbolic acid to sterilize surgical instruments and clean wounds, drastically reducing infections.

The molecular weight of ammonia (NH3) is calculated by adding the atomic masses of one nitrogen atom (approximately 14.007 g/mol) and three hydrogen atoms (approximately 1.008 g/mol each), totaling about 17.031 g/mol, which corresponds to option A.

Soap and detergents remove dirt by lowering the interfacial tension between water and oil/dirt, allowing the dirt to be emulsified and washed away.

When the air temperature is below the freezing point of water, precipitation falls as snow because water vapor freezes directly into ice crystals. Other options like lightning, hailstorms, and thunders are not forms of precipitation caused by freezing air temperature.

Monoatomic gases consist of single atoms rather than molecules. Neon and argon are noble gases that exist as monoatomic gases under standard conditions, unlike nitrogen and oxygen which are diatomic molecules.

Hysteria is a psychological condition and not caused by infectious agents, so it is not contagious. Measles, typhoid, and influenza are all contagious diseases caused by viruses or bacteria that can spread from person to person.

Anthracite coal has the highest carbon content among the types of coal listed, making it the hardest and most energy-rich form of coal. Peat has the least carbon content, followed by lignite and bituminous coal.

Non-stick cooking utensils are coated with Teflon, a brand name for polytetrafluoroethylene (PTFE), which provides a non-stick surface resistant to heat and chemical reactions. The other options like black paint, PVC, and polystyrene are not used for non-stick coatings in cookware.

Aviculture is the practice of keeping and breeding birds, making option B correct. Apiculture refers to beekeeping, while viniculture and viticulture relate to grape cultivation and winemaking, respectively.