Science and General Knowledge Quiz

An average adult human has approximately 4.5 to 5.5 liters of blood. The range 4 to 5 liters is the most accurate among the given choices.

The Moon is Earths natural satellite and the closest celestial body at approximately 384,400 km away, much closer than the Sun or any planet.

Trees grow one annular ring per year in temperate climates. Counting these rings in a cross section of the trunk is the standard method for determining tree age.

When oxygen concentration in blood decreases, the body detects this through chemoreceptors and responds by increasing breathing rate to bring in more oxygen. This is a homeostatic reflex to maintain adequate oxygenation. Options A and C are wrong because breathing doesn't decrease or stay constant. Option D describes a pattern not seen in this reflex.

Calcium oxalate is the most common component of kidney stones, forming when there's excess calcium and oxalate in urine. The other options are not major kidney stone components. Sodium acetate and magnesium sulphate are salts, but pure calcium alone doesn't typically form stones.

Nichrome is an alloy of nickel and chromium that is both hard and ductile, making it useful for heating elements. Carborundum is extremely hard but brittle. Tungsten is very hard but has limited ductility at room temperature. Cast iron is hard but brittle.

Blood glucose is measured in milligrams per deciliter (mg/dL) as the standard medical unit. Millimeters of Hg measures pressure, not concentration. Parts per million is for very dilute solutions. Gram per liter is used but mg/dL is more common in clinical practice.

Carrots are rich in beta-carotene, which the body converts to vitamin A, making them an excellent source. Cereals like wheat and rice are not significant vitamin A sources. Pulses are protein-rich but not vitamin A sources.

The Celsius and Fahrenheit scales intersect at exactly -40 degrees, where -40°C = -40°F. This can be derived from the conversion formula C = (F-32)×5/9. At 0°C, Fahrenheit is 32°F. At 40°C, Fahrenheit is 104°F.

Dialysis is a treatment for kidney failure that artificially removes waste products and excess fluid from blood when kidneys can't function properly. It doesn't treat heart, lungs, or other organs. The kidneys are the primary organs that dialysis replaces.

Ammonia gas is used in cold storage plants for refrigeration.

Aryabhatta, the ancient Indian astronomer (476-550 AD), stated that Earth was spherical in shape in his work Aryabhatiya. Ptolemy and others in the Western world believed in a geocentric model. Copernicus came much later. Pythagoras believed Earth was spherical but Aryabhatta's mathematical treatment was more significant.

Normal human body temperature is approximately 37°C or 98.6°F, so 36.9°C is the closest correct answer. 40.5°C would be fever (high temperature). 98.4°F is close but the Celsius equivalent would be about 37°C, making option B the best choice.

The normal resting heart rate for adults is 60-100 beats per minute, with 72 bpm being a commonly cited average. The range 71-80 bpm is within the normal healthy range and represents the most accurate choice among the options given.

Wind power is a non-conventional or renewable energy source, unlike coal, hydroelectricity (in conventional classification), and natural gas which are considered conventional sources. Wind energy harnesses natural air flow without depleting resources.

During the night, plants undergo respiration rather than photosynthesis, consuming oxygen and releasing carbon dioxide. Sleeping under a tree at night can lead to a lower oxygen and higher carbon dioxide concentration.

Acetylene gas (produced when calcium carbide reacts with water) is commonly used for artificial fruit ripening in commercial settings. Ethylene is the natural ripening hormone, but acetylene mimics its effects.

Joseph Priestley discovered oxygen in 1774 by heating mercuric oxide. He called it 'dephlogisticated air'. Scheele also discovered it independently but Priestley published first.

Vitamin E is known as the 'virility vitamin' or 'anti-sterility vitamin' because it plays a crucial role in reproductive health and fertility. Deficiency can lead to reproductive failure.

Common salt is sodium chloride (NaCl), the most common salt used in food. Sodium bicarbonate is baking soda, magnesium carbonate is a compound in antacids, and calcium carbonate is found in limestone and shells.

Spinning Jenny (1764), Water frame (1769), Power loom (1785), Cotton gin (1793). This sequence matches the historical development of textile machinery during the Industrial Revolution.

A hygrometer measures relative humidity - the amount of water vapor in air relative to the maximum it can hold at that temperature. Atmospheric pressure is measured by a barometer, not a hygrometer.

A sling psychrometer measures relative humidity using two thermometers - one dry bulb and one wet bulb. The difference in readings allows calculation of relative humidity through evaporation cooling.

A sphygmomanometer is the medical instrument used to measure blood pressure. It consists of an inflatable cuff and a mercury or aneroid manometer. Pyrometers measure high temperatures, manometers measure pressure differences, and hygrometers measure humidity.