Everyday Science

A human can generally survive without food for about one month, depending on hydration and health conditions. Survival beyond this period without food is rare and typically not sustainable.

Dialysis is a medical treatment used to perform the function of the kidneys when they fail, by removing waste and excess fluid from the blood. Therefore, it is used in the treatment of kidney failure.

Osmium is the heaviest naturally occurring metal with the highest density, heavier than iron, mercury, and nickel. This makes option D the correct answer.

The volume of carbon dioxide in the air is approximately 0.03%, which corresponds to about 400 parts per million. This is much lower than the other options provided.

A group of elephants is called a 'tower.' While 'herd' and 'mob' can refer to groups of animals, the specific collective noun for elephants is 'tower.'

Iron deficiency in the diet leads to anaemia, a condition characterized by a reduced number of red blood cells or hemoglobin, causing fatigue and weakness. The other options are caused by different deficiencies: goitre by iodine deficiency, scurvy by vitamin C deficiency, and rickets by vitamin D deficiency.

Air is composed mostly of nitrogen, which makes up about 78% of the Earth's atmosphere by volume, making it the gas present in the maximum amount.

Chromium is a metal commonly used in making alloys, such as stainless steel, to improve hardness and corrosion resistance. Gypsum, granite, and limestone are not used in alloy production.

Alnico is an alloy of aluminium, nickel, and cobalt specifically used for making permanent magnets due to its magnetic properties. The other options are aluminium alloys used for structural or mechanical purposes, not for magnets.

The core of a lead pencil is made of graphite, which is a form of carbon, not lead. Hence, carbon is the correct element used in pencils.

One gram of carbohydrates provides approximately 4.1 kilocalories (kcal) of energy, which is the standard value used in nutrition science.

Epsom salt is the common name for magnesium sulfate, a chemical compound with the formula MgSO4. It is widely used in bath salts and as a laxative.

Chlorine acts as a bleaching agent primarily through oxidation, where it breaks down colored compounds by oxidizing them, thus removing color.

Pyrex glass is a type of borosilicate glass known for its high heat resistance, making it suitable for laboratory glassware and cookware. Other types like bottle glass, flint glass, and hard glass do not have the same level of heat resistance.

PVC stands for Polyvinyl chloride, which is a widely used plastic polymer in the industry. The other options are incorrect chemical names that do not correspond to PVC.

The Montgolfier brothers, Joseph-Michel and Jacques-Étienne, are credited with inventing the hot air balloon in the 18th century. They successfully launched the first manned flight in 1783, making option B the correct answer.

A mixture of potassium nitrate, powdered charcoal, and sulphur is known as gunpowder, which is a common explosive and propellant.

Sound travels fastest in solids because the particles are more tightly packed, allowing vibrations to transfer more quickly compared to liquids or gases.

Divers use mixtures of gases as artificial atmospheres to breathe underwater safely. Helium is commonly used as an inert gas to reduce nitrogen narcosis at depth. The other gas used alongside helium is oxygen, not nitrogen. Mixtures like heliox (helium and oxygen) are standard for deep diving to avoid nitrogen narcosis and oxygen toxicity is managed by controlling oxygen partial pressure. Nitrogen is the main inert gas in normal air and nitrox mixtures but is replaced by helium in heliox. Pure oxygen is toxic at depth and carbon monoxide is never used due to its toxicity. Neon is not used in diving gas mixtures. Therefore, the correct answer is oxygen (B).

All usable forms of energy eventually degrade into heat energy due to the second law of thermodynamics, which states that energy transformations increase entropy, often releasing energy as heat.

During photosynthesis, plants and trees take in carbon dioxide and release oxygen as a byproduct. Therefore, the gas they give out during photosynthesis is oxygen.

Atomic clocks are the most accurate devices for measuring very small time intervals due to their use of the consistent frequency of atomic transitions.

Influenza is a viral respiratory infection transmitted mainly through airborne droplets, not water. Cholera, Amoebiasis, and Typhoid are all diseases commonly transmitted through contaminated water, making Influenza the correct answer as it is not waterborne.

Satiety is the feeling of fullness and satisfaction after eating, which leads to a lack of desire to eat more food. Therefore, a patient experiencing satiety lacks the desire to eat.

746 watts is approximately equal to 1 horsepower (HP). This is a standard conversion used in physics and engineering to relate power units.