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This post was last edited by Wang Tianze on 2015-12-13 at 14:10. 77. If the moving contact of the zero potentiometer R35 is open-circuited, then the instrument (B.) still changes in response to signal variations, but the value shown is incorrect. A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change with the variation in the signal, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9; if they are connected in series, the power ratio between the two resistors will be (B. 9:16). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (A. The potential changes depending on the choice of reference point (the zero potential point)). A. The potential changes depending on the choice of reference point (the zero potential point). B. The potential difference also changes depending on the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When maintaining and calibrating instruments, some people have summarized the following rules; which one do you think is incorrect? (D. When replacing the working fluid in an inclinometer micropressure gauge, the specific gravity of alcohol varies little, so it has almost no effect on the instrument.) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precision pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When replacing the working fluid in an inclinometer micropressure gauge, the specific gravity of alcohol varies little, so it has almost no effect on the instrument. Already closed
77. If the moving contact of the zero potentiometer R35 is open, the instrument (b). A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change as the signal changes, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9. If they are connected in series, then the power ratio between the two resistors will be (b). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (a) A. The potential varies depending on the choice of reference point (the zero potential point). B. The potential difference also varies with the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When maintaining and calibrating gauges, some people have summarized the following tips; which one do you think is incorrect? (d) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precise pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When changing the working fluid in an inclined micro-pressure gauge, the specific gravity of alcohol differs little, so it has almost no effect on the gauge
My answers: 77. B. The output changes with the signal, but the value is incorrect. 78. B. 9:16. 79. A. The potential varies depending on the choice of reference point (the zero potential point). 80. D. When changing the working fluid in the inclinometer, the specific gravity of alcohol doesn’t change much, so it has almost no effect on the instrument
77. If the moving contact of the zero potentiometer R35 is open, the instrument ( B ). A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change with changes in the signal, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9. If they are connected in series, then the power ratio between the two resistors will be (B). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (A) A. The potential changes depending on the choice of reference point (the zero potential point). B. The potential difference also changes depending on the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When checking and calibrating instruments, some people have summarized the following tips; which one do you think is incorrect? (D) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precise pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When changing the working fluid in an inclined micro-pressure gauge, the specific gravity of alcohol doesn’t change much, so it has almost no effect on the instrument
77. If the moving contact of the zero potentiometer R35 is open, the instrument ( B ). A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change with changes in the signal, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9. If they are connected in series, then the power ratio between the two resistors will be (B). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (A) A. The potential changes depending on the choice of reference point (the zero potential point). B. The potential difference also changes depending on the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When checking and calibrating instruments, some people have summarized the following tips. Which one do you think is incorrect? ( ) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precise pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When changing the working fluid in an inclinometer micro-pressure gauge, the specific gravity of alcohol differs by very little, so it has almost no effect on the instrument
77. If the moving contact of the zero potentiometer R35 is open, the instrument ( B ). A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change with changes in the signal, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9. If they are connected in series, then the power ratio between the two resistors will be (B). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (A) A. The potential varies depending on the choice of reference point (the zero potential point). B. The potential difference also varies with the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When checking and calibrating instruments, some people have summarized the following tips; which one do you think is incorrect? (D) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precise pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When changing the working fluid in an inclinometer, the specific gravity of alcohol differs by very little, so it has almost no effect on the instrument
77. If the moving contact of the zero potentiometer R35 is open-circuited, the instrument ( A ). A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change with changes in the signal, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9. If they are connected in series, then the power ratio between the two resistors will be (C). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (A) A. The potential changes depending on the choice of reference point (the zero potential point). B. The potential difference also changes depending on the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When checking and calibrating instruments, some people have summarized the following tips. Which one do you think is incorrect? (A) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precise pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When changing the working fluid in an inclined micro-pressure gauge, the specific gravity of alcohol differs little, so it has almost no effect on the instrument
77. If the moving contact of the zero potentiometer R35 is open, the instrument ( B ). A. The instrument does not output any signal, no matter what the differential pressure is. B. The output does change with changes in the signal, but the value is incorrect. C. The instrument indicates the maximum value. D. The instrument indicates zero. 78. For two resistors, when they are connected in parallel, the power ratio between them is 16:9. If they are connected in series, then the power ratio between the two resistors will be (B). A. 4:3 B. 9:16 C. 3:4 D. 16:9 79. Which of the following statements is correct? (A) A. The potential changes depending on the choice of reference point (the zero potential point). B. The potential difference also changes depending on the choice of reference point (the zero potential point). C. If the potentials at two points in a circuit are high, then the voltage between them is also high. D. If the potentials at two points in a circuit are low, then the voltage between them is also low. 80. When checking and calibrating instruments, some people have summarized the following tips; which one do you think is incorrect? (D) A. When the working fluid in a liquid-column pressure gauge is water, a little red ink or another colored substance can be added to the water to facilitate reading. B. In precise pressure measurements, a U-tube pressure gauge cannot use water as its working fluid. C. In winter, alcohol or a mixture of alcohol, glycerin, and water should be used instead of water for calibrating float level gauges. D. When changing the working fluid in an inclined micro-pressure gauge, the specific gravity of alcohol doesn’t change much, so it has almost no effect on the instrument
77. If the moving contact of the zero potentiometer R35 is open-circuited, the instrument (B.) still changes with the signal, but the value is incorrect. 78. Two resistors. When connected in parallel, the power ratio between them is 16:9; if they are connected in series, the power ratio between the two resistors will be (B. 9:16). 79. Which of the following statements is correct? (B. The potential difference changes in value depending on the choice of reference point (the zero potential point)). 80. When reviewing the maintenance and calibration sheets, some people summarized the following experiences; which one do you think is incorrect? (D. When replacing the working fluid in an inclinometer micropressure gauge, the specific gravity of alcohol varies little, so it has almost no impact on the instrument.)
77, B——78, B————79, B————————80, D——————————————————————.