Everyday Science

The "evening star" (usually Venus) appears in the western sky after sunset, so its rising direction is actually in the east, as all celestial bodies rise in the east and set in the west. Therefore, the "rising" of the evening star indicates the east direction.

The sun is primarily composed of plasma, a state of matter where gases are ionized and consist of charged particles. This is due to the extremely high temperatures in the sun's core and outer layers.

Myopia, or nearsightedness, is a condition where distant objects appear blurry while close objects can be seen clearly. Therefore, the correct answer is that myopic individuals have difficulty seeing distant objects clearly.

When coal burns in the absence or lack of oxygen (incomplete combustion), carbon monoxide gas is released instead of carbon dioxide. Carbon monoxide is a toxic gas formed due to incomplete combustion.

Birth control pills contain synthetic hormones, such as estrogen and progestin, which help prevent ovulation and pregnancy. Sugars, vitamins, and minerals are not the active components in these pills.

Scientists identified Improtin-11 as a protein associated with the development and progression of colorectal cancer. Its discovery may help researchers better understand cancer growth and develop targeted treatments in the future.

Transistors do not require a warm-up period because they do not have a filament, unlike vacuum tubes which need their filaments to heat up before functioning properly.

Radiology is the branch of medicine that uses X-rays and other imaging techniques to diagnose and treat diseases. The other options are unrelated fields.

Nylon is a synthetic polymer classified as a polyamide because it contains repeating amide groups (-CONH-) in its backbone. Rayon is a regenerated cellulose fiber, Terylene is a polyester, and Orion is an acrylic fiber, so they are not polyamides.

Hyetology is the branch of meteorology that studies rainfall and precipitation patterns. Therefore, the correct answer is 'Rainfall'.

The proton number, also known as the atomic number, is denoted by the symbol 'Z'. It represents the number of protons in the nucleus of an atom, which defines the element.

Wooden doors absorb water during the rainy season through imbibition, causing the wood to swell and making the doors difficult to open or close. Imbibition is the process of absorption of water by solids causing them to swell.

Convex mirrors are used in anti-shoplifting devices because they provide a wider field of view, allowing shopkeepers to see a larger area and monitor for theft effectively.

The clock is the oldest invention among the options listed. Mechanical clocks date back to the 13th century, whereas the microscope was invented in the late 16th century, the barometer in the 17th century, and the bicycle in the 19th century.

Naphthalene sublimes, turning directly from solid to gas, while sand does not. This property allows separation of the mixture by sublimation, leaving sand behind.

Black soil is also known as Regur soil, which is rich in lime, iron, magnesia, and alumina. It is particularly suitable for growing cotton and is found in regions like the Deccan Plateau in India.

The instrument specifically used for viewing the Sun safely is called a solar telescope (also historically called a heliograph or photoheliograph). However, the term 'heliograph' in modern usage primarily refers to a signaling device that uses sunlight reflection to send messages, not an instrument for viewing the Sun. The options given include 'Stroboscope' (used to view fast-moving objects), 'Heliograph' (signaling device), 'Solograph' (not a recognized instrument), and 'None of these'. Since none of the options correctly name a solar telescope or a proper solar viewing instrument, the correct answer is 'D' (None of these). Viewing the Sun requires specialized solar telescopes or filters to protect the eyes, which are not represented by the other options.

The breath test for drunken driving commonly uses potassium permanganate in sulfuric acid to oxidize ethanol in the breath, causing a color change that indicates alcohol presence. Potassium dichromate is also used in some breath analyzers but the classical chemical test is with potassium permanganate-sulfuric acid.

Conversion of water into steam is a physical change, not a chemical reaction, because it involves a change in state without altering the chemical composition. The other options involve chemical changes where new substances are formed.

Silver is the best conductor of electricity among metals, better than copper, gold, and lead, making it the purest conductor in terms of electrical conductivity.

Silicon-based compounds, such as silicones, are commonly used in beauty parlours for hair setting because they provide smoothness, shine, and hold to the hair. Sulphur, chlorine, and phosphorus are not typically used for hair setting purposes.

Composting is the biological process of converting wet organic waste into manure or nutrient-rich soil conditioner through decomposition by microorganisms.

Brass gets discoloured in air primarily due to the presence of hydrogen sulphide gas, which reacts with the copper in brass to form copper sulphide, causing tarnishing and discoloration.

The Tyndall effect refers to the scattering of light by particles in a colloid or in very fine suspensions. This scattering makes the path of the light visible, which is why option C, scattering, is correct.

Selenium is a non-metal that exhibits semiconducting properties, meaning it can conduct electricity better than typical poor conductors like sulphur, bromine, and phosphorus, which are generally electrical insulators. Therefore, selenium is the correct answer as it is not a poor conductor of electricity among the options.