Everyday Science

Gas bills are typically charged using units from the International System of Units (SI) or related standard units. Common billing units include volume-based units such as CCF (hundreds of cubic feet) and MCF (thousands of cubic feet), which measure the volume of gas, and energy-based units such as therms and British Thermal Units (BTU), which measure the energy content of the gas. Therms and BTUs are not systems of units but individual units within or related to SI. The SI system includes cubic meters for volume and joules or kilowatt-hours for energy, which are standard in many regions. CGS is not used for gas billing, and CNG refers to compressed natural gas, not a unit system. Therefore, the best answer is SI, as gas billing relies on SI units or related standard units for measurement and billing.

Acetyl salicylic acid is commonly known as Aspirin, a widely used medication for pain relief, fever reduction, and anti-inflammatory purposes. The other options are different drugs with distinct chemical compositions and uses.

Wheat typically contains about 245 kilocalories per 100 grams, making option B the most accurate choice. The other options either underestimate or overestimate the energy content significantly.

Vitamin D is synthesized in the skin when it is exposed to sunlight, specifically ultraviolet B rays. This makes sunbathing a natural source of vitamin D for the human body.

In traditional analog electricity meters, the digit or dial at the extreme right represents the 'ones' place, meaning it counts single units of kilowatt-hours (kWh). Each complete revolution of this dial corresponds to one full unit (1 kWh) of electricity consumed. The next dial to the left represents tens, then hundreds, and so forth. Therefore, the rightmost digit represents 1/10th of a unit is incorrect; it actually represents 1 unit (or 1 kWh). However, since the options do not include '1 unit,' the closest correct interpretation is that the rightmost digit represents the 'ones' place, which corresponds to 1 unit. The option '1/10th of the unit' is the closest to this concept, as the other options (1/5th, 1/100, 1/1000) are not correct. Digital meters display the reading directly in kWh, so the rightmost digit is the ones place as well. Hence, the correct answer is C: 1/10th of the unit is not exactly correct but is the closest among the given options, and the explanation should clarify that the rightmost digit represents the ones place (1 unit).

The word 'science' comes from the Latin 'scientia,' which means 'knowledge.' This is the root meaning that underpins the modern concept of science as systematic knowledge.

Calcium sulphate is commonly known as gypsum. It is a mineral used in construction and agriculture. Therefore, 'Gypsum salt' is the correct name for calcium sulphate.

Carbon monoxide is highly toxic because it binds to hemoglobin in the blood more effectively than oxygen, preventing oxygen transport and leading to poisoning. The other gases listed are either non-toxic or less harmful at typical exposure levels.

Earth rotates on its axis approximately every 23 hours 56 minutes 4 seconds, which is a sidereal day, but it revolves around the Sun in about 365.25 days. The question asks about Earth's rotation around the Sun, which is its revolution period, not rotation period. None of the options correctly state the Earth's revolution period, so 'None of the above' is correct.

Chlorine is commonly used in water purification to kill harmful bacteria and pathogens, making water safe to drink. Bromine is less commonly used, plants do not purify water chemically, and 'Young man' is irrelevant.