1. Which one of the following SI unit prefix definitions is not correct? (a) 1 u
ID: 861242 • Letter: 1
Question
1. Which one of the following SI unit prefix definitions is not correct? (a) 1 um 1x106m (b) 1 ns 1x109 s (c) 1 Mbyte 1x106 bytes (d) 1 kca 1x103 cal (e) 1 cl 1x102 L 2. In the calculation 1.02x104 divided by 9.8088x109, how many significant figures should you report in the answer? (a) 1 (b) 2 (c) 3 (d) 4 (e) 5 3. Which one of the following statements is most likely to be a scientific law? (a) E m.c2 (b) Magnesium is a metal, found mostly as a compound on Earth in the form of magnesium carbonate or sulfate. (c) A neutron is a subatomic particle. (d) The surface of the Earth is covered by thin rock layers that move, causing earthquakes when one layer moves against another. (e) The sky is blue. 4. Which one of the following steps follows an observation in the scientific method? (a) Prediction. (b) Hypothesis (c) Revised hypothesis. (d) Theory (e) Experiment. 5. What is 320 Gbytes in bytes, written in scientific notation? (a) 3.20x10 11 bytes. (b) 3.20x10 9 bytes (c) 3.20x109 bytes (d) 3.20x 1010 bytes (e) 3. 20x1011 bytes 6. What are the correct chemical symbols for sodium, gold, mercury and tin? (a) So, Au, Hg, Ti (b) Na, Au, Hg, Sn (c) Na, Go, Me, Ti (d) Na, Au, Mg, Sn (e) Si, Gd, Mg, Ti 7. Which one of the following is a physical change? (a) The conversion of co2 and water into o2 and sugar by a photosynthetic plant. (b) Melting lead. (c) Making sodium chloride from sodium metal and chlorine gas. (d) Iron rusting. (e) The combustion of natural gas.Explanation / Answer
Answers with explanation:
1. d) 1 kcal = 1*10-3 cal
because 1kcal is 1 kilo calorie and 1 kilo = 103
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2. c) 3
because any operation has final result with same number of significant figures as the value with the least in the question. Here 1.02 * 10-4 has 3 significant figures.
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3. c) A neutron is a subatomic particle
Because it has been experimentally discovered and proved under all circumstances that neutron exists as subatomic particle. Rest statements are correct under particular circumstances.
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4. b) Hypothesis
Hypothesis follows Observation in scientific methods.
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5. e) 3.20 * 1011 bytes
Can be proved after calculations.
1 GB = 109 Byte as Giga means 109
So 320 GB = 3.20 * 102 * 109
= 3.20 * 1011 bytes
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6. b) Na,Au,Hg,Sn
They represent the correct sequence of names- Sodium Na, Gold Au, Mercury -Hg, Tin -Sn
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7. b) Melting lead
Rest all are chemical changes
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