2 8 13 2 26 Fe Iron 55.845 2 8 14 2 27 Co Cobalt 58.933195 2 8 15 2 28 Ni Nickel 58.6934 2 8 16 2 29 Cu Copper 63.546 2 8 18 1 30 31 Zn Zinc 65.38 Ga Gallium 69.723 2 8 18 3 32 Ge Germanium 72.64 2 8 18 4 33 As Arsenic 74.92160 2 8 18 5 34 Se Selenium 78.96 2 8 18 6 35 Br Bromine 79.904 2 8 18 7 36 Kr Krypton 83.798 2 8 18 8 K L M N Potassium 39.0983 37 5 Rb 55 2 8 18 8 1
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dewees (vd866) – Exam review – dewees – (24127) This print-out should have 35 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Elements can be distinguished by their 1. hardness. 2. transparency. 3. dissolves in carbon disulfide 4. density of 2.07 g/ml 005 10.0 points Which of these substances I) table salt II) the liquid called coffee III) mercury is a mixture? 3. brittleness. 1. II and III only 4. density. 2. All
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Timeline of materials technology BC • 29‚000–25‚000 BC – First pottery appears • 3rd millennium BC – Copper metallurgy is invented and copper is used for ornamentation • 2nd millennium BC – Bronze is used for weapons and armour • 16th century BC – The Hittites develop crude iron metallurgy • 13th century BC – Invention of steel when iron and charcoal are combined properly • 10th century BC – Glass production begins in ancient Near East • 1st millennium BC – Pewter beginning to be used in
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Transistor A transistor is a semiconductor device used to amplify and switch electronic signals. It is made of a solid piece of semiconductor material‚ with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor’s terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power‚ the transistor provides amplification of a signal. Today
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Chemistry Reference Tables Name Avogadro’s number Value 6.022 × 1023 particles/mole 0.0821 L atm mole K L mmHg 62.4 mole K 8.314 L kPa mole K 1.00 atm = 101.3 kPa = 760. mmHg = 760. torr 0°C or 273K 22.4 L Symbol Value Gas constant (R) Standard pressure Standard temperature Volume of 1 mole of any gas at STP Thermodynamic Constants Heat of fusion of water Heat of vaporization of water H f (water) Hv (water) 334 J/g 2‚260 J/g J for ice‚ 2.02 J for steam‚ g°C g°C J for liquid 4.18
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The single-transistor inverter circuit illustrated earlier is actually too crude to be of practical use as a gate. Real inverter circuits contain more than one transistor to maximize voltage gain (so as to ensure that the final output transistor is either in full cutoff or full saturation)‚ and other components designed to reduce the chance of accidental damage. Shown here is a schematic diagram for a real inverter circuit‚ complete with all necessary components for efficient and reliable operation:
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CPU: Past‚ Present‚ Future Table of Contents Introduction…………………………………………………………………………………….3 CPU………………………………………………………………………………….…3 CU………………………………………………………………………………………3 ALU…………………………………………………………………………………….3 Register…………………………………………………………………………………4 Bus………………………………………………………………………………………4 Past………………………………………………………………………………………………4 1st Generation…………………………………………………………………..………..5 2nd Generation…………………………………………………………………….....…..5 3rd Generation………………………………………………………………………..…..6 4th Generation……………………………………………………………………………6
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How to Solder First a few safety precautions: * Never touch the element or tip of the soldering iron. They are very hot (about 400°C) and will give you a nasty burn. * Take great care to avoid touching the mains flex with the tip of the iron. The iron should have a heatproof flex for extra protection. An ordinary plastic flex will melt immediately if touched by a hot iron and there is a serious risk of burns and electric shock. * Always return the soldering iron to its stand when
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OPTICAL FIBRE TRANSMISSION A SEMINAR PAPER SUBMITTED TO THE INSTITUTE OF SCIENCE LABORATORY TECHNOLOGY FACULTY OF SCIENCE EKITI STATE UNIVERSITY BY AKINLEMIBOLA DAMILOLA JOE MATRIC NO: 050230 IN PARTIAL FUFILLMENT OF THE B.SC HONOURS DEGREE IN PHYSICS ELETRONICS NOV 2011 1 CERTIFICATION This is to certify that this seminar work was carried out by Akinlemibola Damilola Joe‚ Matriculation Number 050230‚ in the Department of Physics Electronics‚ Institute of Science Laboratory
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CHAPTER 3: CRYSTAL STRUCTURES & PROPERTIES ISSUES TO ADDRESS... • How do atoms assemble into solid structures? (for now‚ focus on metals) • How does the density of a material depend on its structure? • When do material properties vary with the sample (i.e.‚ part) orientation? Chapter 3- 1 ENERGY AND PACKING • Non dense‚ random packing Energy typical neighbor bond length typical neighbor bond energy • Dense‚ regular packing r Energy typical neighbor bond length
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