HW #1-solutions

# HW #1-solutions - Agha (sa9896) – HW 1 – bohm –...

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Unformatted text preview: Agha (sa9896) – HW 1 – bohm – (59970) 1 This print-out should have 20 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points What is the standard form for 2 × 10 − 3 ? 1. . 002 correct 2. 20 3. 200 4. . 2 5. . 0002 6. . 02 7. 2000 8. 2 Explanation: The exponent is negative, so the number is less than 1. The decimal is to be moved 3 places, so the number is 0 . 002. 002 10.0 points Express 0.0103240 in scientific notation. 1. 1 . 0324 × 10 − 1 2. 1 . 03240 × 10 − 2 correct 3. 1 . 0324 × 10 − 2 4. 1 . 0324 × 10 − 3 5. 1 . 03240 × 10 2 6. 1 . 03240 × 10 − 3 Explanation: The number is a fraction smaller than one, so the exponent is negative. The decimal must be moved 2 places, so the exponent on 10 must be- 2. 003 10.0 points The quantity 8 . 7 × 10 5 g expressed in stan- dard decimal notation is 1. 870,000 g. correct 2. 0.000087 g. 3. 0.0000087 g. 4. 870.000 g. Explanation: The exponent on 10 is positive, so the num- ber is > 1; the decimal must be moved 5 places. 004 10.0 points Express 3.90 × 10 − 4 in decimal notation. 1. 39,000 2. 0.00039 3. 0.000390 correct 4. 3.900 Explanation: 3.90 × 10 − 4 means move the decimal 4 places to the left to get 0.000390. 005 10.0 points A proton (P) and a neutron (N) each weigh 1 . 68 × 10 − 24 g gram. An electron weighs 9 . 1 × 10 − 28 g gram. b b Electrons N P Find the mass of one helium atom, which contains 2 protons, 2 neutrons and 2 electrons. 1. None of these 2. 6 . 72182 × 10 − 24 g correct Agha (sa9896) – HW 1 – bohm – (59970) 2 3. 6 . 72364 × 10 − 24 4. 1 . 68091 × 10 − 24 5. 3 . 36364 × 10 − 24 Explanation: The mass is 4 · ( 1 . 68 × 10 − 24 g ) + 2 · ( 9 . 1 × 10 − 28 g ) = (4 · 1 . 68) × 1 × 10 − 24 g + (2 · 9 . 1) × 1 × 10 − 28 g = 6 . 72182 × 10 − 24 g 006 10.0 points Given 1 inch ≡ 2 . 54 cm and 1 foot ≡ 12 inches, how many square centimeters are there in 3 . 65 ft 2 ? 1. 81 . 4682 cm 2 2. 111 . 252 cm 2 3. 3390 . 96 cm 2 correct 4. . 00997922 cm 2 5. . 00392883 cm 2 6. 1 . 96236 cm 2 7. 282 . 58 cm 2 8. . 119751 cm 2 Explanation: 3 . 65 ft 2 × (12 inch ft ) 2 × (2 . 54 cm inch ) 2 = 3390 . 96 cm 2 007 10.0 points Convert 29 . 5 mi / h to m/s. 1 mi = 1609 m....
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## This note was uploaded on 11/03/2008 for the course PHY 302K taught by Professor Kaplunovsky during the Spring '08 term at University of Texas at Austin.

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HW #1-solutions - Agha (sa9896) – HW 1 – bohm –...

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