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Serway_CP_poll_ch17

Serway_CP_poll_ch17 - Suppose that a voltage surge produces...

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Suppose that a voltage surge produces 140 V for a moment in a 120 V-line. What will temporarily be the output of a 100 W lightbulb assuming its resistance does not change? 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 109 W 2. 118 W 3. 127 W 4. 136 W
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A solar panel measures 80 cm x 50 cm. In direct sunlight, the panel delivers 3.2 A at 15 V. If the intensity of sunlight is 1000 W/m 2 , what is the efficiency of the solar panel in converting solar energy into electrical energy? 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 24.0% 2. 18.0% 3. 12.0% 4. 6.0%
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A steam turbine at an electric power plant delivers 4500 kW of power to an electrical generator which converts 95% of this mechanical energy into electrical energy. What is the current delivered by the generator if it delivers at 3600 V? 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0.66 x 10 3 A 1.0 x 10 3 A 1.19 x 10 3 A 5.9 x 10 3 A
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The heating coil of a hot water heater has a resistance of 20 ohm and operates at 210 V. How long a time is required to raise the temperature of 200 kg of water from 15°C to 80 °C? (the specific heat for water = 10 3 cal/kg-°C and 1.0 cal = 4.186 J) 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 1.7 hr 2. 3.8 hr 3. 5.1 hr 4. 6.9 hr
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The heating coil of a hot water heater has a resistance of 20 ohm and operates at 210 V. If electrical energy costs 5.5 cents per kW-hr, what does it cost to raise the 200 kg water temperature form 15°C to 80°C? (the specific heat of water = 10 3 cal/kg°C and 1.0 cal = 4.186 J) 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 48 cents 2. 83 cents 3. 16 cents 4. 80 cents
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An electric clothes dryer draws 15 A at 220 V. If the clothes put into the dryer have a mass of 7 kg when wet and 4 kg dry, how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water, L vap = 2.26 x 10 6 J/kg.) 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 55.1 min 2. 34.2 min 3. 20.0 min 4. 15.6 min
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By what factor is the resistance of a copper wire changed when its temperature is increased from 20°C to 120°C? (the temperature coefficient of resistivity for copper = 3.9 x 10 -3 /°C) 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 0.72 2. 1.06 3. 1.39 4. 1.44
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If a lamp is measured to have a resistance of 120 ohms when it operates at a power of 100 W, what is the applied voltage? 1 2 3 4 25% 25% 25% 25% 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1. 110 V 2. 120 V 3. 125 V 4. 220 V
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If a lamp has a resistance of 120 ohms when it operates at a power of 100 W, what current does the lamp carry?
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