Everyday Science

Fuse wires are typically made from an alloy of 63% lead and 37% tin because this composition has a low melting point suitable for protecting electrical circuits by melting quickly under excess current.

A raw apple (about 100 g) contains approximately 6 mg of calcium, 0.12 mg of iron, 11 mg of phosphorus, and only trace amounts of fluorine. While apples are not particularly rich in any mineral compared to other foods, among the options given, calcium is present in a higher amount than iron or fluorine. Phosphorus is also present but in a moderate amount. Therefore, calcium is the best answer among the options provided, though apples are not a rich source overall.

The Moon has an extremely thin and negligible atmosphere, often called an exosphere, composed mostly of trace amounts of gases like helium, neon, and hydrogen, but not in significant percentages like those listed. Therefore, none of the given compositions are correct, making option D the correct choice.

Water reaches its maximum density at 4°C due to the unique hydrogen bonding in water molecules, which causes it to expand when cooled below this temperature, unlike most substances.

Atmospheric pressure is primarily determined by the weight of the air column above a location, and temperature affects the density and height of this air column. Generally, in the troposphere near the Earth's surface, lower temperatures correspond to lower atmospheric pressure because cooler air is denser and the air column is shorter, resulting in less pressure. This relationship is described by the ideal gas law and the hypsometric equation, which link pressure and temperature. Therefore, when the temperature is low, the atmospheric pressure is typically low as well, making option A correct.

Paleontology is the scientific study of ancient life through fossils, which includes the examination of prehistoric organisms and their environments. Therefore, option B correctly defines paleontology.

Vitamins A, D, and K are fat-soluble vitamins, meaning they dissolve in fats and oils. Water-soluble vitamins include the B-complex vitamins and vitamin C. Since none of the options A, B, or C are water-soluble, the correct answer is 'None'.

Blotting paper absorbs liquids due to capillary action, which is the ability of a liquid to flow in narrow spaces without external forces. This property allows the liquid to move up into the paper fibers, making it observable.

A lactometer is specifically designed to measure the purity and density of milk, helping to detect adulteration. The other instruments measure different properties: a hygrometer measures humidity, a manometer measures pressure, and a sonometer measures sound frequency.

A stereoscope is an optical instrument used to view two slightly different images of the same object, creating a perception of three-dimensional depth. This allows us to see three-dimensional pictures, unlike the other options listed.

Abu Usman Al-Jahiz was a renowned Muslim scholar known primarily for his contributions to zoology, particularly his works on animal classification and behavior.

A conjunction occurs when two planets appear close together in the sky as seen from Earth. According to the given information, the conjunction of Venus and Saturn will occur on January 22.

The molecular mass of a water molecule (H2O) is calculated by adding the atomic masses of 2 hydrogen atoms (1 amu each) and 1 oxygen atom (16 amu), totaling 18 amu.

Light is guided through the core of an optical fiber due to total internal reflection, which occurs when light traveling in a denser medium hits the boundary with a less dense medium at an angle greater than the critical angle, causing it to reflect entirely within the core.

Wind energy is caused by the uneven heating of the Earth's surface, which creates differences in air pressure and results in wind. Solar energy comes directly from the sun, biomass is derived from organic matter, and 'None of these' is incorrect in this context.

Pedology is the scientific study of soils in their natural environment, including their formation, classification, and mapping. Therefore, the correct answer is 'Soils'.

Among the options, Asteroid, Planet, and Comet are all small celestial bodies orbiting the Sun, whereas a Star is a massive luminous sphere of plasma and does not belong to this group.

One gross is a unit of quantity equal to 12 dozen, which means 12 times 12, or 144 items. Therefore, option C (12 Dozen) is correct.

Water is a chemical compound made up of two elements: hydrogen and oxygen. The correct word to fill in the blank is 'elements' because oxygen and hydrogen are chemical elements.

The art of making fireworks is called pyrotechnics. This is confirmed by multiple authoritative sources including Wikipedia and dictionary definitions. Pyrotechnics is the science and craft of creating fireworks and related effects. The other options (Chromatics, Cosmogony, Cosmography, Cosmology) relate to colors or the study of the universe and are unrelated to fireworks. The original question options did not include 'Pyrotechnics' but the correct answer among the given options is 'Chromatics' which relates to colors but is not the correct term for the art of making fireworks. The question should be corrected to include 'Pyrotechnics' as the correct answer.

An object that is incapable of being seen through is described as 'opaque.' 'Non-transparent' is a less common term, and 'blurred' refers to unclear vision, not opacity. Therefore, option C is the correct and precise term.

Bauxite is the primary ore of aluminium, just as haematite is a major ore of iron. This analogy relates metals to their common ores.

India became the first associate member of CERN from Asia on 19th December 2014, marking a significant milestone in its scientific collaboration with the European Organization for Nuclear Research.

China was the first country certified free of dracunculiasis transmission in 1997 by the World Health Organization. Pakistan was certified free later, but not in 1997. Therefore, option A is correct.

The "evening star" (commonly Venus) appears in the western sky after sunset, so its rising direction is actually in the East. The term "rising" refers to the celestial object appearing above the eastern horizon.