Science and technology

Q.1 Which of these has the highest calorific value? A. Rubber B. Hydrogen C. Coal D. Plastic E. Wood Explanation:- When fuels are burnt, heat is produced. The amount of heat produced by different types of fuels on burning is expressed in terms of calorific value. Calorific value of a fuel may be defined as the amount of heat produced on complete burning of 1 gm of fuel. S.I. unit of calorific value of fuels is kilojoule per gram (KJ/g). For example, when one gram of wood is burnt completely it produces 17 kilojoules heat. Therefore, the calorific value of wood is 17 KJ/g. in similar manner, when 1 gm of kerosene oil is burnt completely it produces 48 kilojoules heat. So, the calorific value of kerosene oil is 48 KJ/g. the calorific value of different types of fuels is given in following table. Table of calorific value of fuels Serial No. Fuel Calorific value 1. Hydrogen 150 KJ/g 2. Methane 55 KJ/g 3. LPG 50 KJ/g 4. Kerosene oil 48 KJ/g 5. Charcoal 33 KJ/g 6. Wood 17 KJ/g Signi...

Q.1 If an analog clock is broken and not moving anymore.How many times a day will it show        the correct time?       A.Zero       B.One       C.Two       D.Three Answer:-Two

Q.1 There are rings around which of the following?       A. Uranus       B. Mars       C. Jupiter       D. Saturn                     Answer :-D Q,2 Thermometer is related to degree in the same way as clock is related to       A. Wall       B. Tower      C. Hour      D. Cock Answer:C Q.3 The solar eclipse occurs when       A. the sun comes in between the moon and the earth       B. the earth comes in the between the sun and the moon       C. the moon comes in between the sun and the earth       D. None of the above Answer:C

Q.1 Which Star is called Earth’s satellite? Q.2 What is the Orbital period of Moon?                       Answer:-1 Earth has many satellites orbiting it, but the only significant natural satellite that orbits the Earth is the moon. The Union of Concerned Scientists (UCS) maintains a listing of all man-made satellites orbiting the Earth, which includes more than 1,000 operating satellites. Full Answer More than 500 of these man-made satellites are operated by the United States, with more than 100 also coming from Russia and China. The UCS Satellite Database is a free and comprehensive database that allows people to find information about the various satellites including altitude and mission. Users are able to find answers to popular questions, such as the number of satellites a given country has in orbit and their specific usage. The moon is Earth's only significant natural satellite, and it is believed to be approximately 4.5 bill...

Q.1 The use of chemicals or drugs to selectively distroy infectious micro-organism without                        destroying the live tissues, or the host,is known as       A.Chemotherapy       B.Gene therapy       C.Drug therapy       D.Plastic surgery Answer:-A Q.2 Gun powder, which is an explosive comprises of charcoal, sulphur and       A. glycerine       B. salt petre       C. nitro glycerine       D. dynamite Answer: Option B Q.3 Gelatine which is a nitrogenous organic protein is obtained by the hydrolysis of       A. collagen       B. tannin       C. molasses       D. carbohydrate Answer: Option A

Q.1 Why it keeps us awake,why you think we feel sleepy sometimes even when we are not tired,the          reason is a hormone       A.Adrenaline       B.Adenosine       C.Thyroxine       D.Secrotonine Answer:-B Q.2 Cooking and baking is one of the major activities we do daily that involves chemistry.A chemical        frequently used in baking soda....       A.Sodium bicarbonate       B.Sodium chloride       C.Sodium hydroxide       D.Hydrogen peroxide Answer:-A Q.3 Yogurt,breads, cakes and many other products are formed by multiplication of certain useful                bacteria and the process is called        A.Dehydration        B.Fermentaion        C.Calcination        D.Dehydroge...