AccelePrep for the ACT Test 2nd Edition Student Text

C HAPTER 12 | T RY I T O UT ! S CIENCE P RACTICE • 231

20. After studying the measurement made in the previous question, as well as those made earlier in Experiments 1, 2, and 3, the experimenter could reasonably hypothesize that: F. voltage measured across a resistor is inversely proportional to the value of that resistor. G. voltage measured across a resistor is directly proportional to the value of that resistor. H. voltage measured across a resistor is not related to the value of that resistor. J. voltage measured across a resistor equals the battery voltage. 21. When the experimenter recorded the current in the circuit of Experiment 1, it measured 0.003 amperes. In Experiment 3, however, the current measured 0.002 amperes. These results show that current and total resistances are: A. directly proportional. B. inversely proportional. C. equal. D. unrelated. 22. Which of the following formulas for the current in the circuit best summarizes the above results? (The battery voltage is given by V b and the total resistance is given by R .) F. V b R G. V R b H. V R b J. V R b 23. A new circuit is set up, similar in design to those in the experiments. The battery voltage and the size of the resistors are unknown, but the current measures 0.001 amperes. If the battery voltage is doubled and one of the two resistors is replaced with one having a smaller value, which answer most accurately describes the new current? A. It will be smaller than 0.001 amperes. B. It will be unchanged. C. It will be greater than 0.001 amperes. D. Cannot be determined from the given information

PASSAGE IV Using electrical circuits, three experiments were performed to investigate the relationship between voltage (volts), resistance (ohms) (total resistance of resistors in series equals the sum of individual resistances), and current (amperes). Each experiment was set up with the following circuit design: Experiment 1 Using a 6 volt battery and two 1,000 ohm resistors (R 1 and R 2 ), the measured voltages between points 1 and 2 and between points 2 and 3 were 3 volts each. Experiment 2 When the battery voltage was increased to 12 volts, and the resistors were kept the same (1,000 ohms each), the measured voltages between points 1 and 2 and between points 2 and 3 were 6 volts each. Experiment 3 Using the original 6 volt battery, R 1 was replaced with a 2,000 ohm resistor. The voltages measured between points 1 and 2 and between points 2 and 3 were 4 volts and 2 volts, respectively. 19. Judging from the results in Experiment 1 and Experiment 2, if the battery voltage were changed to 1.5 volts and both resistors were 1,000 ohms, what voltage would be expected between point 1 and point 2? A. 0.75 volts B. 1.5 volts C. 3.0 volts D. 6.0 volts