General Science Questions (MCQs) for Competitive Examinations

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Silicone hydrogel and regular hydrogel lenses both are made of plastics that are hard when dry but readily absorb water and become soft and gel-like when hydrated. They are most commonly used in making Contact Lenses.

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Millets are a group of highly variable small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. It is usually considered a separate cereal, but sometimes also known as great millet.

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Leishmaniasis is a disease caused by protozoan parasites that belong to the genus Leishmania and is transmitted by the bite of certain species of Sandflies. The disease can present in three main ways: cutaneous, mucocutaneous, or visceral.

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Chlorophyll is a green photosynthetic pigment found in plants, algae, Ferns & Mosses. involved in photosynthesis, the process by which light energy is converted to chemical energy through the synthesis of organic compounds.

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Cirrhosis is a late stage of scarring (fibrosis) of the liver caused by many forms of liver diseases and conditions, such as hepatitis and chronic alcoholism. Alcoholism is the most common cause of cirrhosis in the world. It occurs when the liver is damaged over time and cannot function properly, leading to scarring and eventually cirrhosis.

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Lemurs are part of the primate group. They are native to the island of Madagascar, making it one of the few places in the world where primates naturally inhabit. Unlike some other primates, lemurs are non-violent and generally social creatures. They are known for their distinctive “song”, often performed in a group chorus, which can be heard from a distance. This unique primates are also known for their large, round reflective eyes and wailing cries.

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Hematocrit levels are used in doping tests of Athletes , (the RBCs are carriers of Oxygen). hematocrit levels also denotes the blood iron. hematocrit levels of 38 or higher are normally suitable for the donors to donate their blood. Here please note that sometimes its is asked in exams about the ion which can help better in blood coagulation and normally options given are Ca, Na, K & Fe+3. The obvious answer is Fe+3.

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For reasons of safe transportation of fruits, mangoes, bananas etc are picked before they ripen fully. Slightly green harvested mangoes are subjected to small containers of calcium carbide (CaC2) with a plastic covering. CaC2 reacts with the moisture in the air to release acetylene (or ethyne) gas as follows:
CaC2 + 2 H2O – C2H2 + Ca(OH)2
This option may give you slightest confusion if you don’t know the difference between Ethylene and Ethyne (Acetylene). Both are chemical substances produced by fruits to accelerate the normal process of fruit maturation — is a ripening hormone. Ethylene is C2H4 and has a carbon-carbon double bond. Acetylene is C2H2 and has a carbon-carbon triple bind. Acetylene contains more energy and burns hotter than ethylene. Ethylene is a gaseous compound , Acetylene is the chemical compound , which is the simplest alkyne and is also a hydrocarbon while Ethylene is the simplest alkene and classified as an unsaturated hydrocarbon. I hope you will never forget it now.

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The acceleration of an object at a given instant of time is called Instantaneous acceleration. When an object moves with variable acceleration, then it possesses different acceleration at different point of time.

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The minimum speed required to put a satellite into a given orbit around earth is known as Orbital velocity of the satellite. Orbital velocity (v) = (GM/r)^1/2 where G= gravitational constant, M= mass of the earth and r = radius of the orbit of the satellite.