Circuits

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3. Which circuit is built so that if one lightbulb goes out, the other three lightbulbs will continue to glow? If this one goes out The others go out. Home The other three bulbs will continue to glow. This is a parallel circuit. F, G, H above are series circuits. If this one goes out 54

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5. Which switch, if opened, will cause the light bulb to stop glowing? F Q G R H S J T Home If R was opened/off, the electricity would still go through S to the bulb. If T was opened/off, the electricity would still go through S to the bulb. If S was opened/off, the electricity would still go through R and T to the bulb. If Q was opened/off, the electricity would NOTmake it to the bulb. Battery 32

6. Home How much current is flowing through this circuit? A 0.32 A B 3.1 A C 4.0 A D 12.5 A Current = 4 ÷ 12.5 47

7. What is the current in a copper wire that has a resistance of 2 ohms and is connected to a 9-volt electrical source? F 0.22 amp G 4.5 amps H 11.0 amps J 18.0 amps Home Current (frequency) Frequency = voltage ÷ resistance(ohms) ? = 9 ÷ 2 46

8. Home Energytransformation Back to energy conservation of energy convection, conduction, and radiation energy sources

9. Assuming the chart contains all energy transformations in the Earth system, how much solar radiation goes toward evaporating water? F 40,000 terajoules G 92,410 terajoules H 121,410 terajoules J 133,410 terajoules Home Back to energy Add these together: And subtract from the whole: 173,410 – 133,410 = = 133,410 52

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11. Which process best shows the conversion of solar energy to chemical energy? F Prevailing winds causing windmills to spin G Green plants making their own food H Uranium producing heat to make steam J Tides generating electricity Home Back to energy Plants use the sun more efficiently than anything known to mankind. 14

12. Which of the following is an example of solar energy being converted into chemical energy? F Plants producing sugar during the day G Water evaporating and condensing in the water cycle H The sun unevenly heating Earth’s surface J Lava erupting from volcanoes for many days Home Back to energy Sugar is chemical energy. It has calories and joules. 12

13. An inventor claims to have created an internal combustion engine that converts 100 kJ of chemical energy from diesel fuel to 140 kJ of mechanical energy. This claim violates the law of conservation of — F momentum G inertia H energy J mass Home Back to energy chemical energy = mechanical energy + heat 48

14. Home Back to energy Energy = 2 x 2 x 4.184

15. This experiment probably was set up to determine — A how much mechanical energy the battery produces B the pH of water during electrolysis C the pressure created by an electric current D how much energy is converted to heat Home Back to energy A thermometer 9

16. Home Back to energy Container P and Container Q each were filled with 0.5 liter of water. The water was heated to 90°C. The table shows the temperatures after both containers were allowed to cool for 3 minutes. Compared to Container Q, Container P is a better — A conductor B absorber C radiator D insulator Small change. Larger change. 43

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18. The energy not stored in the bonds of the carbon dioxide and water must have left in the form of heat. Home Back to energy ≠ + = + Reactants = Products Why is the sum of the products’ energy in this reaction less than the sum of the reactants’ energy? A Energy is given off as heat. B The products absorb available energy. C Energy is trapped in the reactants. D The reactants’ energy is less than the melting point of glucose. 37

19. After Home Back to energy The illustrations show a conservation-of-mass experiment. The solution in the beaker lost mass because — F materials have less mass at high temperatures G the mass of the reactants and products was less than 100 g H sodium sulfate (Na2SO4) is lighter than air J some of the water molecules turned into gas Before Some of the water evaporated because of the heat. After( less than 100 g) Before(100 g) 30 REACTANTS →Products The sum of the reactants = the sum of the products.

20. An inventor claims to have created an internal combustion engine that converts 100 kJ of chemical energy from diesel fuel to 140 kJ of mechanical energy. This claim violates the law of conservation of — F momentum G inertia H energy J mass Home Back to energy chemical energy = mechanical energy + heat 48

21. Home Back to energy Batteries and fuel cells change chemical energy into electrical energy. Fuel cells powered by plankton from the seabed can be used to operate instruments that monitor ocean currents and water temperature. These fuel cells get their energy by converting — F chemical energy to electrical energy G electrical energy to mechanical energy H hydroelectric energy to geothermal energy J mechanical energy to chemical energy 16

22. Heat convection occurs in gases and liquids. Heat convection does not occur in solids because solids are unable to — A absorb heat by vibrating B transfer heat by fluid motion C emit radiation by reflecting light D exchange heat by direct contact Home Back to energy 43

23. The moon’s surface becomes hot during the long lunar day because the sun transfers heat to the moon. This heat transfer is accomplished almost entirely through the process of — F convection G refraction H conduction J radiation The space between planets has no elements in it and is therefore called a “vacuum”. Only radiation can travel through a vacuum. Convection and conduction use atoms to transfer energy. Home Back to energy 8

24. In which container is the substance unable to transfer heat by convection? Home Back to energy Gases and liquid can convect. 42

25. The primary way liquids and gases transmit heat is by the process of — F reflection G conduction H radiation J convection Home Back to energy Gases and liquid can convect. 2

26. Rule: Conduction: solids Convection: liquids and gases Radiation: doesn’t need matter at all Compression: does not apply to this question. Home Back to energy A man who was sleeping wakes up because he hears the smoke alarm go off in his house. Before opening the bedroom door, the man feels the door to see whether it is warm. He is assuming that heat would be transferred through the door by — A conduction B convection C radiation D compression 33

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28. Home Back to energy Batteries and fuel cells change chemical energy into electrical energy. Fuel cells powered by plankton from the seabed can be used to operate instruments that monitor ocean currents and water temperature. These fuel cells get their energy by converting — F chemical energy to electrical energy G electrical energy to mechanical energy H hydroelectric energy to geothermal energy J mechanical energy to chemical energy 16

29. Home Back to energy Battery-powered cars produce less air pollution than gasoline-powered cars. However, one environmental concern of using battery-powered cars is that batteries — A are heavier than gasoline engines B waste more energy than gasoline engines C contain toxic substances that are difficult to dispose of D produce direct current rather than alternating current 49

30. In West Texas and Southern California, high winds drive turbines that generate electricity. One advantage that wind energy has over energy generated from solar cells is that wind energy — A is plentiful everywhere B can be generated at night C produces cleaner energy D is free of environmental hazards Home Back to energy 45